diff --git a/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini b/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
index 3605e8f3fc9..76b44d9e9cf 100644
--- a/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
@@ -4,7 +4,7 @@
     expected: TIMEOUT
 
   [Opening a blob URL in a new window immediately before revoking it works.]
-    expected: TIMEOUT
+    expected: FAIL
 
   [Fetching a blob URL immediately before revoking it works in an iframe.]
     expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
deleted file mode 100644
index 4bfb0c2053a..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-004.html]
-  [Miss float below something else]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini b/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
index 4a1e8110f6f..f8e7e539aae 100644
--- a/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
@@ -2,3 +2,6 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
+  [Hit test within unscaled box]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
index b2f3f00d5b4..d080f72a962 100644
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
@@ -8,12 +8,6 @@
   [throws if handleEvent is thruthy and not callable]
     expected: FAIL
 
-  [looks up handleEvent method on every event dispatch]
-    expected: FAIL
-
-  [calls handleEvent method of event listener]
-    expected: FAIL
-
   [doesn't look up handleEvent method on callable event listeners]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-iframes.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-iframes.html.ini
index 6ef8bb1049f..171592fc08f 100644
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-iframes.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-iframes.html.ini
@@ -2,6 +2,3 @@
   [elementsFromPoint on the root document for points in iframe elements]
     expected: FAIL
 
-  [elementsFromPoint on inner documents]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
index ab63c03ee2a..13bea363fb6 100644
--- a/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
@@ -330,3 +330,9 @@
   [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
+  [<iframe>: separate response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
index 25318ac5846..d2df9b78483 100644
--- a/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
@@ -53,6 +53,6 @@
   [combined text/javascript ]
     expected: FAIL
 
-  [separate text/javascript error]
+  [separate text/javascript x/x]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
index b290d442952..61682d248e2 100644
--- a/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,9 +11,6 @@
   [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20%22nosniFF%22]
-    expected: FAIL
-
-  [Content-Type-Options%3A%20nosniff]
+  [X-Content-Type-Options%3A%20%40%23%24%23%25%25%26%5E%26%5E*()()11!%2Cnosniff]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
deleted file mode 100644
index 87b07c3e670..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_1.html]
-  [Multiple history traversals from the same task]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
deleted file mode 100644
index 75d75b4cda2..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_2.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
similarity index 71%
rename from tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
rename to tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
index 75d75b4cda2..385376c7321 100644
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_2.html]
+[traverse_the_history_4.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
deleted file mode 100644
index dc2e45516de..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_5.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index e63fe7c263e..c6f45be1eb2 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_escaping-2.html]
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
index 295031c1812..338d283eb0e 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_escaping-3.html]
-  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
-    expected: TIMEOUT
+    expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 1b74d6e073d..0c89d5253df 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
@@ -1,4 +1,5 @@
 [iframe_sandbox_popups_nonescaping-1.html]
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
index 0407f0cc2b7..9eb581fcf1f 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_nonescaping-2.html]
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
index 7a36937927c..f4f994c5d6f 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
@@ -1,4 +1,5 @@
 [iframe_sandbox_popups_nonescaping-3.html]
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: FAIL
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/form-double-submit.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/form-double-submit.html.ini
new file mode 100644
index 00000000000..b193c33c2b6
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/form-double-submit.html.ini
@@ -0,0 +1,4 @@
+[form-double-submit.html]
+  [default submit action should supersede onclick submit()]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
deleted file mode 100644
index bcd2fd0eab8..00000000000
--- a/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[077.html]
-  [ adding several types of scripts through the DOM and removing some of them confuses scheduler ]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini
deleted file mode 100644
index a817ad54be7..00000000000
--- a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[load-event-after-location-set-during-write.window.html]
-  [Setting location from document.write() call should not trigger load event until that load completes]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
index 57744023f73..58c9d7f8c0c 100644
--- a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
@@ -1,5 +1,5 @@
 [ignore-opens-during-unload.window.html]
-  expected: CRASH
+  expected: TIMEOUT
   [document.open should bail out when ignore-opens-during-unload is greater than 0 during visibilitychange event (open(parent) while unloading parent and child)]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini
new file mode 100644
index 00000000000..7c54bdba7be
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini
@@ -0,0 +1,4 @@
+[processing-after-resume.https.html]
+  [Test consistency of processing after resume()]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini
new file mode 100644
index 00000000000..1d689678029
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini
@@ -0,0 +1,17 @@
+[suspend-after-construct.html]
+  expected: ERROR
+  [Stop waiting]
+    expected: NOTRUN
+
+  [State change counting]
+    expected: TIMEOUT
+
+  [Iteration 2]
+    expected: NOTRUN
+
+  [Iteration 3]
+    expected: NOTRUN
+
+  [Iteration 1]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata-layout-2020/webmessaging/with-ports/017.html.ini b/tests/wpt/metadata-layout-2020/webmessaging/with-ports/017.html.ini
deleted file mode 100644
index 064cf47545b..00000000000
--- a/tests/wpt/metadata-layout-2020/webmessaging/with-ports/017.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[017.html]
-  expected: TIMEOUT
-  [origin of the script that invoked the method, about:blank]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata-layout-2020/webmessaging/with-ports/018.html.ini b/tests/wpt/metadata-layout-2020/webmessaging/without-ports/018.html.ini
similarity index 100%
rename from tests/wpt/metadata-layout-2020/webmessaging/with-ports/018.html.ini
rename to tests/wpt/metadata-layout-2020/webmessaging/without-ports/018.html.ini
diff --git a/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini b/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini
deleted file mode 100644
index 80f9a4f15b8..00000000000
--- a/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[Worker-constructor.html]
-  expected: ERROR
diff --git a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
index faa00f45ecf..d4f62ed7113 100644
--- a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
+++ b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
@@ -7,7 +7,7 @@
     expected: FAIL
 
   [Opening a blob URL in a new window immediately before revoking it works.]
-    expected: TIMEOUT
+    expected: FAIL
 
   [Opening a blob URL in a noopener about:blank window immediately before revoking it works.]
     expected: TIMEOUT
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index fa96003525c..c6b99982361 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -123443,6 +123443,19 @@
        {}
       ]
      ],
+     "float-inside-small-block.html": [
+      "2afd6dacc9c1f910be33a97677c0f5841fe5b035",
+      [
+       null,
+       [
+        [
+         "/css/reference/ref-filled-green-100px-square.xht",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "floats-and-text-narrow-and-short-dynamic.html": [
       "09e5021555d50ca0c6919082bfffc81652f65092",
       [
@@ -128228,6 +128241,658 @@
        {}
       ]
      ],
+     "content-visibility": {
+      "content-visibility-001.html": [
+       "1c3eb90e3a7935bf1f9973a2ab7fb3d0d0e04960",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-002.html": [
+       "75e02633f3a5f218092e490fac9a8e2fa5bd700b",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-with-child-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-003.html": [
+       "08eb3a1288b5610cdbefad23f8c02e9e50e4e0b8",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/content-visibility-003-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-004.html": [
+       "b02d0a82468e2b3d3b1f7e7fb7bf2f05499136a3",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/content-visibility-004-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-005.html": [
+       "06e8eb892518c03051d2ebea04899f916ec4f314",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-006.html": [
+       "5c51a1fcd8587f00ad90180cd7fb214b1da077a2",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-007.html": [
+       "087900e0b18ec297abb69e104a1dc3ee6277d870",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-008.html": [
+       "40d7265aca420df119224caaa8e2ffb8e0fb9a64",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-009.html": [
+       "30944e391dc51413b10826f087baa128a6946eab",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/positioned-container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-010.html": [
+       "8d3f054ac105c6686084bb976b99ad2d68fcc69e",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-011.html": [
+       "ea0decb06c7cdc3d2f355fa5f0bdde92bcb026ed",
+       [
+        null,
+        [
+         [
+          "/css/css-contain/content-visibility/positioned-container-ref.html",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "content-visibility-012.html": [
+       "fab0ded7c1ae5a5cedc528efcb825e5fe9546b07",
+       [
+        null,
+        [
+         [
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+     "e46d6b6caa594d722f7502d06c18c13513e97213",
      [
       "cookie-store/cookieListItem_attributes.tentative.https.any.html",
       {
@@ -381697,7 +382512,7 @@
      ]
     ],
     "cookieStore_delete_arguments.tentative.https.any.js": [
-     "f1763ad7cbecaf36caaf583f3681288b09e6e43b",
+     "5989dcb8be6b3e93adebbfd456898c7dba40e1f9",
      [
       "cookie-store/cookieStore_delete_arguments.tentative.https.any.html",
       {
@@ -382050,7 +382865,7 @@
      ]
     ],
     "cookieStore_set_arguments.tentative.https.any.js": [
-     "528bc9de6c1f45ff4389fec4096a9e4432892770",
+     "aab964d014eca3b341c1e772c677d2af71d8756e",
      [
       "cookie-store/cookieStore_set_arguments.tentative.https.any.html",
       {
@@ -382083,7 +382898,7 @@
      ]
     ],
     "cookieStore_special_names.tentative.https.any.js": [
-     "0cf4edc75437ba336bc78da8c016295c44362ffe",
+     "db077478e0eebb143664c651123a32bb5fc1e722",
      [
       "cookie-store/cookieStore_special_names.tentative.https.any.html",
       {
@@ -386556,6 +387371,204 @@
        {}
       ]
      ],
+     "content-visibility": {
+      "content-visibility-015.html": [
+       "6099054ebd04ec742e7db84110b957c592318f43",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-016.html": [
+       "db3599e24352ea1d02e33b6b7145feb2444136a8",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-017.html": [
+       "a9c0e0300965770ba6d2971f1cc7917cb5580778",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-018.html": [
+       "15fe7f769d768be087e1cef39d4bb5edac376b59",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-026.html": [
+       "d0815186edb90dd016d238ca1eaeb928dce0c979",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-029.html": [
+       "759863467808ec777790152a4e379b0b1f5f61eb",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-030.html": [
+       "397f8de519f08e00764ff00b8dac331c4d9d401c",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-031.html": [
+       "134b1c18f73d978e9f113cddd223dfdfa21cb8d9",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-035.html": [
+       "e7f922a0d34bd3ef2c769833d80534cb0ae889bc",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-036.html": [
+       "8dc56e9145418425f86cd9c5eb3a79967a09b8e8",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-038.html": [
+       "638a336c912aefeeec82ab96041ac8b9e3584a56",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-039.html": [
+       "481dcc45831bd1891c70c36d9fe7d6ab1211ba61",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-044.html": [
+       "bf4f6168d414e87a6f16b450274c5887e28ec36e",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-047.html": [
+       "8a3cde252f0cc164203b61b278a2e3dd5485753d",
+       [
+        null,
+        {
+         "testdriver": true
+        }
+       ]
+      ],
+      "content-visibility-048.html": [
+       "2b8679b5dd6c7a003bd8cb5f307c0a85b0e3078c",
+       [
+        null,
+        {
+         "testdriver": true,
+         "timeout": "long"
+        }
+       ]
+      ],
+      "content-visibility-050.html": [
+       "bcc4f5e430c1b5f4de514426ea468a8128496d31",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-053.html": [
+       "ebdaecbc62b56d84bf2408445f0d896b89571eb0",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-054.html": [
+       "232dc0d7b118bda131245b03adfa52dea89e7569",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-068.html": [
+       "330256adb29805cd8a84ec1449a3a1812d7f6370",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-069.html": [
+       "89cbd1dc93bb54e4f0da0163009fc9904e0ecca5",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-070.html": [
+       "4f63069edde41369ff6e9d5b71c9e1f32b479fd0",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-071.html": [
+       "6f267b27c7ea07f6ec4b19bef9d2dd78b4f06c76",
+       [
+        null,
+        {}
+       ]
+      ],
+      "content-visibility-072.html": [
+       "9fc8b11ceb280784f2aff19c9006ea35ada56a26",
+       [
+        null,
+        {}
+       ]
+      ],
+      "inheritance.html": [
+       "e1ae8164de00467a450511da9ca4bf7f138e9c71",
+       [
+        null,
+        {}
+       ]
+      ],
+      "parsing": {
+       "content-visibility-computed.html": [
+        "6e08deebea07a40fe40350de7b02dfd516a98633",
+        [
+         null,
+         {}
+        ]
+       ],
+       "content-visibility-invalid.html": [
+        "610e219e1bae60b57925520044c959dfb3de2bd9",
+        [
+         null,
+         {}
+        ]
+       ],
+       "content-visibility-valid.html": [
+        "a0525695ded5ac8717f1d85cc791a82ed3f6f7bf",
+        [
+         null,
+         {}
+        ]
+       ]
+      }
+     },
      "inheritance.html": [
       "07378a29f39db8bdf100aa04c60cb23f556d962b",
       [
@@ -395276,6 +396289,13 @@
        {}
       ]
      ],
+     "contain-paint-offscreen-container.html": [
+      "58f41cc748027b6fc41d3dfaa4f9cb8432629d57",
+      [
+       null,
+       {}
+      ]
+     ],
      "descend-into-container-with-float.html": [
       "ff39608ff04090cde9bfb0a3eeafc15bfeb5a191",
       [
@@ -407875,7 +408895,7 @@
       ]
      ],
      "prefers-reduced-data.html": [
-      "003dad4c8b6a45a8b8959baaedf54031102a0bbf",
+      "4c2668fe78ed0804304e0b7b5699d780b99c789b",
       [
        null,
        {}
@@ -472350,6 +473370,13 @@
         {}
        ]
       ],
+      "dynamic-childlist-002.html": [
+       "d874e80bbba6cccb88fe5e79c51af72b087d75e3",
+       [
+        null,
+        {}
+       ]
+      ],
       "href-click-3.html": [
        "1b7f0685e65e7c939caab3d546316e7bf858f885",
        [
@@ -476326,7 +477353,7 @@
    },
    "native-io": {
     "close_async.tentative.https.any.js": [
-     "a992f93eb5307fd435cb46e593f1a04e47e970c6",
+     "6ad27ffb4478262578a69b62b15acc496f81f81e",
      [
       "native-io/close_async.tentative.https.any.html",
       {
@@ -476389,7 +477416,7 @@
      ]
     ],
     "close_sync.tentative.https.any.js": [
-     "8897d66f2cc297df0876d83026d219f05d8160fc",
+     "e4f5871a65e6bab61a5df808d8f88a9d28494373",
      [
       "native-io/close_sync.tentative.https.any.worker.html",
       {
@@ -476407,7 +477434,7 @@
      ]
     ],
     "concurrent_io_async.tentative.https.any.js": [
-     "abc2031d5f9aec4f885f39d9db18331444af811d",
+     "d7752004678ef2762dc0ec01736bf1d81ef4cb25",
      [
       "native-io/concurrent_io_async.tentative.https.any.html",
       {
@@ -477752,147 +478779,147 @@
    },
    "origin-isolation": {
     "going-back.sub.https.html": [
-     "781e3640d3b37f373e81fa0b92e4623ed0c462af",
+     "7e95f19366996ce0c97b87631b10d660d07c2e56",
      [
       null,
       {}
      ]
     ],
     "insecure-http.sub.html": [
-     "04d4b2b636502ec79397bca45fd59cda807e150e",
+     "1e78b13385727e0cbb091b6469d1e7c9c0905093",
      [
       null,
       {}
      ]
     ],
     "parent-no-child-bad-subdomain.sub.https.html": [
-     "2653dabd980b8caf65cf84b4765a2cfc0c4cb5c9",
+     "ae55f5d83e10ad6c5e0cda383fc02d8f8690a8bf",
      [
       null,
       {}
      ]
     ],
     "parent-no-child-yes-same.sub.https.html": [
-     "4239e1644638b04d330ff70f8a27e97f5af88ab0",
+     "8e32649d3a2d23cef359bedfae318bafbf3ca1c8",
      [
       null,
       {}
      ]
     ],
     "parent-no-child-yes-subdomain.sub.https.html": [
-     "f2389eaa6a02ccb42f232e35f1c4600ddbf92fa6",
+     "7f4a9413e35702c0831f808bc64cc78cb2b6e1fe",
      [
       null,
       {}
      ]
     ],
     "parent-no-child-yes-with-params-subdomain.sub.https.html": [
-     "164a19ff381f9f351af805cf8ff73ddac92bafb1",
+     "0208ac3e14c66e61f1c49bcb20c31d7ab1faf50b",
      [
       null,
       {}
      ]
     ],
     "parent-no-child1-no-child2-yes-children-different.sub.https.html": [
-     "3c879391a4571398a4254a15906411d5e844c596",
+     "c019ef2fe7dfd026e59eff7a7a3e294d6601c576",
      [
       null,
       {}
      ]
     ],
     "parent-no-child1-no-child2-yes-children-same.sub.https.html": [
-     "5d9161a852f71695922b49015257846150b6408b",
+     "9ca18f8941b37553d3797554d7e77d1260c1ce01",
      [
       null,
       {}
      ]
     ],
     "parent-no-child1-yes-child2-no-children-same.sub.https.html": [
-     "d289c8821aebf767c485967b5455b1e5badb3f1a",
+     "2947e629bd51d71dfa179c04ae0dc32aaac00097",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child-no-same.sub.https.html": [
-     "a1b9e4e3f5a230e8e49d3552d338d48f029d07cd",
+     "aa1dd94682ea817c0a7af881837d71da583517a1",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child-no-subdomain.sub.https.html": [
-     "b167b1b4954080c57ed718996f50ff2c6586a9ad",
+     "5055d295d03711917378895392f44bbe783adc2b",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child-yes-same.sub.https.html": [
-     "f43526cd5529fc8346c338545f9cbba99769cb7e",
+     "3d99486a3cb517763f68872a67217607f4c27777",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child-yes-subdomain.sub.https.html": [
-     "5c3567cee570757305189263ed6149392b3c4fd5",
+     "afc8f5b2acdf9eb8f0d92f2bb60df47fe379468b",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-no-child2-no-children-different.sub.https.html": [
-     "ad1e58a16c1cc62634da9c0cae67b64424ef3b18",
+     "77a77d50a1c83f5e75731131c1d3133f8fba3dc3",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-no-child2-no-children-same.sub.https.html": [
-     "ceed3a562f0740d13b77f4068eaa7c38563ab321",
+     "b3f18e8560f7f392f9128af291037013abbc9493",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-no-child2-yes-children-different.sub.https.html": [
-     "6b09b36a586b5cc6c8f306f47afce99709359252",
+     "8e7b4d3ee5c4b1c659c44327a5c34e008f60e871",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-no-child2-yes-children-same.sub.https.html": [
-     "b3616a604b9c4e1288e1da8ddce3e9b3a224ba6c",
+     "260ac80d2ff4ae91b144827790f49df71960224d",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-yes-child2-no-children-same.sub.https.html": [
-     "7e351aaf14a008d9788e3fcfd481ca19138be2f0",
+     "ae54fcd02ea8e16a576161d83d1fc4b5844e1c39",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-yes-child2-yes-children-different.sub.https.html": [
-     "f7c7ea81459999fc05a25f335fdfb409a05e0fa9",
+     "775f753561b3864603796c1bbfb91976371cf040",
      [
       null,
       {}
      ]
     ],
     "parent-yes-child1-yes-child2-yes-children-same.sub.https.html": [
-     "ca5528e5096081e1789167ca306d1c97d7ae3214",
+     "a3b0939862ce4d4043c45a607350f70e34f221fb",
      [
       null,
       {}
      ]
     ],
     "removing-iframes.sub.https.html": [
-     "0d2d97815e2a624cacd8d841e6dd35e38f01250d",
+     "2f01562b04cc83bc379088f5e660b130db44bfd1",
      [
       null,
       {}
@@ -493206,7 +494233,7 @@
      ]
     ],
     "getScreens.values.https.html": [
-     "5ce54839deefc78a9da98f7283d71c55705281f8",
+     "3d70a7c81cf6548f28dbe8fbfb7c438901e03060",
      [
       null,
       {}
@@ -514507,6 +515534,20 @@
         null,
         {}
        ]
+      ],
+      "processing-after-resume.https.html": [
+       "e000ab124fefa6f0eea4e5517d04436428c0cd8c",
+       [
+        null,
+        {}
+       ]
+      ],
+      "suspend-after-construct.html": [
+       "596a825c3db8b02e645cb1098222e89e737e12cb",
+       [
+        null,
+        {}
+       ]
       ]
      },
      "the-audionode-interface": {
@@ -515019,7 +516060,7 @@
        ]
       ],
       "suspended-context-messageport.https.html": [
-       "5f5b10a251f41fd29f694564a717587f8a5a0bad",
+       "f6fa6ddd98613016ff9aeb92aa2929aa81e20f75",
        [
         null,
         {}
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
deleted file mode 100644
index 4bfb0c2053a..00000000000
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-004.html]
-  [Miss float below something else]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/css-transforms/backface-visibility-hidden-006.html.ini b/tests/wpt/metadata/css/css-transforms/backface-visibility-hidden-006.html.ini
new file mode 100644
index 00000000000..f2bd6a325be
--- /dev/null
+++ b/tests/wpt/metadata/css/css-transforms/backface-visibility-hidden-006.html.ini
@@ -0,0 +1,2 @@
+[backface-visibility-hidden-006.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini b/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
index 4a1e8110f6f..f8e7e539aae 100644
--- a/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
+++ b/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
@@ -2,3 +2,6 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
+  [Hit test within unscaled box]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini b/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
index a6c39d50087..d080f72a962 100644
--- a/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
+++ b/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
@@ -8,3 +8,6 @@
   [throws if handleEvent is thruthy and not callable]
     expected: FAIL
 
+  [doesn't look up handleEvent method on callable event listeners]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/cssom-view/elementsFromPoint-iframes.html.ini b/tests/wpt/metadata/css/cssom-view/elementsFromPoint-iframes.html.ini
index 6ef8bb1049f..171592fc08f 100644
--- a/tests/wpt/metadata/css/cssom-view/elementsFromPoint-iframes.html.ini
+++ b/tests/wpt/metadata/css/cssom-view/elementsFromPoint-iframes.html.ini
@@ -2,6 +2,3 @@
   [elementsFromPoint on the root document for points in iframe elements]
     expected: FAIL
 
-  [elementsFromPoint on inner documents]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/fetch/content-type/response.window.js.ini b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
index e238a790ed2..46cc294317d 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -330,3 +330,9 @@
   [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
+  [<iframe>: separate response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/fetch/content-type/script.window.js.ini b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
index 25318ac5846..d2df9b78483 100644
--- a/tests/wpt/metadata/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
@@ -53,6 +53,6 @@
   [combined text/javascript ]
     expected: FAIL
 
-  [separate text/javascript error]
+  [separate text/javascript x/x]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
index b290d442952..61682d248e2 100644
--- a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,9 +11,6 @@
   [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20%22nosniFF%22]
-    expected: FAIL
-
-  [Content-Type-Options%3A%20nosniff]
+  [X-Content-Type-Options%3A%20%40%23%24%23%25%25%26%5E%26%5E*()()11!%2Cnosniff]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
deleted file mode 100644
index 87b07c3e670..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_1.html]
-  [Multiple history traversals from the same task]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
similarity index 71%
rename from tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
rename to tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
index dc2e45516de..385376c7321 100644
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_5.html]
+[traverse_the_history_4.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index e63fe7c263e..c6f45be1eb2 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_escaping-2.html]
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
index 5f60c78e73c..f6a7aca3306 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
@@ -1,6 +1,5 @@
 [iframe_sandbox_popups_escaping-3.html]
   type: testharness
-  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
-    expected: TIMEOUT
+    expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 3f7e3e9544f..4bc0524f105 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
@@ -1,5 +1,6 @@
 [iframe_sandbox_popups_nonescaping-1.html]
   type: testharness
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
index d43f38b40cd..45d8be1c898 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
@@ -1,6 +1,6 @@
 [iframe_sandbox_popups_nonescaping-2.html]
   type: testharness
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
index dc856a3d5a3..e440b1e38c6 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
@@ -1,5 +1,6 @@
 [iframe_sandbox_popups_nonescaping-3.html]
   type: testharness
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: FAIL
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini
new file mode 100644
index 00000000000..b193c33c2b6
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/forms/form-submission-0/form-double-submit.html.ini
@@ -0,0 +1,4 @@
+[form-double-submit.html]
+  [default submit action should supersede onclick submit()]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
deleted file mode 100644
index bcd2fd0eab8..00000000000
--- a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[077.html]
-  [ adding several types of scripts through the DOM and removing some of them confuses scheduler ]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini
deleted file mode 100644
index a817ad54be7..00000000000
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/closing-the-input-stream/load-event-after-location-set-during-write.window.js.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[load-event-after-location-set-during-write.window.html]
-  [Setting location from document.write() call should not trigger load event until that load completes]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
index 910c88d3e81..69bd952d756 100644
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
+++ b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
@@ -1,5 +1,5 @@
 [ignore-opens-during-unload.window.html]
-  expected: CRASH
+  expected: TIMEOUT
   [ignore-opens-during-unload]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini
new file mode 100644
index 00000000000..7c54bdba7be
--- /dev/null
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html.ini
@@ -0,0 +1,4 @@
+[processing-after-resume.https.html]
+  [Test consistency of processing after resume()]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini
new file mode 100644
index 00000000000..1d689678029
--- /dev/null
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html.ini
@@ -0,0 +1,17 @@
+[suspend-after-construct.html]
+  expected: ERROR
+  [Stop waiting]
+    expected: NOTRUN
+
+  [State change counting]
+    expected: TIMEOUT
+
+  [Iteration 2]
+    expected: NOTRUN
+
+  [Iteration 3]
+    expected: NOTRUN
+
+  [Iteration 1]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/webmessaging/with-ports/017.html.ini b/tests/wpt/metadata/webmessaging/with-ports/017.html.ini
deleted file mode 100644
index 064cf47545b..00000000000
--- a/tests/wpt/metadata/webmessaging/with-ports/017.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[017.html]
-  expected: TIMEOUT
-  [origin of the script that invoked the method, about:blank]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata/webmessaging/with-ports/018.html.ini b/tests/wpt/metadata/webmessaging/without-ports/018.html.ini
similarity index 100%
rename from tests/wpt/metadata/webmessaging/with-ports/018.html.ini
rename to tests/wpt/metadata/webmessaging/without-ports/018.html.ini
diff --git a/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini b/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini
deleted file mode 100644
index 80f9a4f15b8..00000000000
--- a/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[Worker-constructor.html]
-  expected: ERROR
diff --git a/tests/wpt/mozilla/meta-layout-2020/mozilla/promise.html.ini b/tests/wpt/mozilla/meta-layout-2020/mozilla/promise.html.ini
deleted file mode 100644
index 317601f6fb8..00000000000
--- a/tests/wpt/mozilla/meta-layout-2020/mozilla/promise.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[promise.html]
-  [Native promise from async callback can be resolved]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/meta/mozilla/promise.html.ini b/tests/wpt/mozilla/meta/mozilla/promise.html.ini
index e5ac0e78cd9..784c666e1b7 100644
--- a/tests/wpt/mozilla/meta/mozilla/promise.html.ini
+++ b/tests/wpt/mozilla/meta/mozilla/promise.html.ini
@@ -1,6 +1,3 @@
 [promise.html]
   type: testharness
   prefs: [dom.testbinding.enabled:true]
-  [Native promise from async callback can be resolved]
-    expected: FAIL
-
diff --git a/tests/wpt/web-platform-tests/cookie-store/cookieListItem_attributes.tentative.https.any.js b/tests/wpt/web-platform-tests/cookie-store/cookieListItem_attributes.tentative.https.any.js
index 344277382dd..e46d6b6caa5 100644
--- a/tests/wpt/web-platform-tests/cookie-store/cookieListItem_attributes.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/cookie-store/cookieListItem_attributes.tentative.https.any.js
@@ -52,8 +52,8 @@ promise_test(async testCase => {
 promise_test(async testCase => {
   await cookieStore.delete('cookie-name');
 
-  await cookieStore.set('cookie-name', 'cookie-value',
-                        { expires: kTenYearsFromNow });
+  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
+                          expires: kTenYearsFromNow });
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
@@ -73,27 +73,7 @@ promise_test(async testCase => {
   await cookieStore.delete('cookie-name');
 
   await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
-                          expires: kTenYearsFromNow });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie.name, 'cookie-name');
-  assert_equals(cookie.value, 'cookie-value');
-  assert_equals(cookie.domain, null);
-  assert_equals(cookie.path, '/');
-  assert_approx_equals(cookie.expires, kTenYearsFromNow, kOneDay);
-  assert_equals(cookie.secure, true);
-  assert_equals(cookie.sameSite, 'strict');
-  assert_array_equals(Object.keys(cookie).sort(), kCookieListItemKeys);
-}, 'CookieListItem - cookieStore.set with name and value in options and ' +
-   'expires set to a future timestamp');
-
-promise_test(async testCase => {
-  await cookieStore.delete('cookie-name');
-
-  await cookieStore.set('cookie-name', 'cookie-value',
-                        { expires: new Date(kTenYearsFromNow) });
+                          expires: new Date(kTenYearsFromNow) });
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
@@ -107,31 +87,11 @@ promise_test(async testCase => {
 }, 'CookieListItem - cookieStore.set with expires set to a Date 10 ' +
    'years in the future');
 
-promise_test(async testCase => {
-  await cookieStore.delete('cookie-name');
-
-  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
-                          expires: new Date(kTenYearsFromNow) });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie.name, 'cookie-name');
-  assert_equals(cookie.value, 'cookie-value');
-  assert_equals(cookie.domain, null);
-  assert_equals(cookie.path, '/');
-  assert_approx_equals(cookie.expires, kTenYearsFromNow, kOneDay);
-  assert_equals(cookie.secure, true);
-  assert_equals(cookie.sameSite, 'strict');
-  assert_array_equals(Object.keys(cookie).sort(), kCookieListItemKeys);
-}, 'CookieListItem - cookieStore.set with name and value in options and ' +
-   'expires set to a future Date');
-
 promise_test(async testCase => {
   await cookieStore.delete({ name: 'cookie-name', domain: kCurrentHostname });
 
-  await cookieStore.set('cookie-name', 'cookie-value',
-                        { domain: kCurrentHostname });
+  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
+                          domain: kCurrentHostname });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', domain: kCurrentHostname });
   });
@@ -153,8 +113,8 @@ promise_test(async testCase => {
       currentPath.substr(0, currentPath.lastIndexOf('/') + 1);
   await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
 
-  await cookieStore.set('cookie-name', 'cookie-value',
-                        { path: currentDirectory });
+  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
+                          path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -175,8 +135,8 @@ promise_test(async testCase => {
   const currentDirectory = currentPath.substr(0, currentPath.lastIndexOf('/'));
   await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
 
-  await cookieStore.set('cookie-name', 'cookie-value',
-                        { path: currentDirectory });
+  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value',
+                          path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -211,23 +171,4 @@ promise_test(async testCase => {
     assert_array_equals(Object.keys(cookie).sort(), kCookieListItemKeys);
   }, `CookieListItem - cookieStore.set with sameSite set to ${sameSiteValue}`);
 
-  promise_test(async testCase => {
-    await cookieStore.delete('cookie-name');
-
-    await cookieStore.set('cookie-name', 'cookie-value',
-                          { sameSite: sameSiteValue });
-    testCase.add_cleanup(async () => {
-      await cookieStore.delete('cookie-name');
-    });
-    const cookie = await cookieStore.get('cookie-name');
-    assert_equals(cookie.name, 'cookie-name');
-    assert_equals(cookie.value, 'cookie-value');
-    assert_equals(cookie.domain, null);
-    assert_equals(cookie.path, '/');
-    assert_equals(cookie.expires, null);
-    assert_equals(cookie.secure, true);
-    assert_equals(cookie.sameSite, sameSiteValue);
-    assert_array_equals(Object.keys(cookie).sort(), kCookieListItemKeys);
-  }, 'CookieListItem - cookieStore.set with positional name and value and ' +
-     `sameSite set to ${sameSiteValue}`);
 });
diff --git a/tests/wpt/web-platform-tests/cookie-store/cookieStore_delete_arguments.tentative.https.any.js b/tests/wpt/web-platform-tests/cookie-store/cookieStore_delete_arguments.tentative.https.any.js
index f1763ad7cbe..5989dcb8be6 100644
--- a/tests/wpt/web-platform-tests/cookie-store/cookieStore_delete_arguments.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/cookie-store/cookieStore_delete_arguments.tentative.https.any.js
@@ -22,35 +22,25 @@ promise_test(async testCase => {
   assert_equals(cookie, null);
 }, 'cookieStore.delete with name in options');
 
-promise_test(async testCase => {
-  await cookieStore.set('cookie-name', 'cookie-value');
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-
-  await cookieStore.delete('cookie-name', { name: 'wrong-cookie-name' });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie, null);
-}, 'cookieStore.delete with name in both positional arguments and options');
-
 promise_test(async testCase => {
   const currentUrl = new URL(self.location.href);
   const currentDomain = currentUrl.hostname;
 
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: `.${currentDomain}` }));
+      { name: 'cookie-name', value: 'cookie-value',
+        domain: `.${currentDomain}` }));
 }, 'cookieStore.delete domain starts with "."');
 
 promise_test(async testCase => {
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: 'example.com' }));
+      { name: 'cookie-name', value: 'cookie-value', domain: 'example.com' }));
 }, 'cookieStore.delete with domain that is not equal current host');
 
 promise_test(async testCase => {
   const currentUrl = new URL(self.location.href);
   const currentDomain = currentUrl.hostname;
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: currentDomain });
+      { name: 'cookie-name', value: 'cookie-value', domain: currentDomain });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
   });
@@ -81,50 +71,13 @@ promise_test(async testCase => {
 }, 'cookieStore.delete with domain set to a non-domain-matching suffix of ' +
    'the current hostname');
 
-promise_test(async testCase => {
-  const currentUrl = new URL(self.location.href);
-  const currentDomain = currentUrl.hostname;
-  await cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: currentDomain });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
-  });
-
-  await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie, null);
-}, 'cookieStore.delete with name in options and domain set to the current ' +
-   'hostname');
-
-promise_test(async testCase => {
-  const currentUrl = new URL(self.location.href);
-  const currentDomain = currentUrl.hostname;
-  const subDomain = `sub.${currentDomain}`;
-
-  await promise_rejects_js(testCase, TypeError, cookieStore.delete(
-      { name: 'cookie-name', domain: subDomain }));
-}, 'cookieStore.delete with name in options and domain set to a subdomain of ' +
-   'the current hostname');
-
-promise_test(async testCase => {
-  const currentUrl = new URL(self.location.href);
-  const currentDomain = currentUrl.hostname;
-  assert_not_equals(currentDomain[0] === '.',
-      'this test assumes that the current hostname does not start with .');
-  const domainSuffix = currentDomain.substr(1);
-
-  await promise_rejects_js(testCase, TypeError, cookieStore.delete(
-      { name: 'cookie-name', domain: domainSuffix }));
-}, 'cookieStore.delete with name in options and domain set to a ' +
-   'non-domain-matching suffix of the current hostname');
-
 promise_test(async testCase => {
   const currentUrl = new URL(self.location.href);
   const currentPath = currentUrl.pathname;
   const currentDirectory =
       currentPath.substr(0, currentPath.lastIndexOf('/') + 1);
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: currentDirectory });
+      { name: 'cookie-name', value: 'cookie-value', path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -141,7 +94,7 @@ promise_test(async testCase => {
       currentPath.substr(0, currentPath.lastIndexOf('/') + 1);
   const subDirectory = currentDirectory + "subdir/";
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: currentDirectory });
+      { name: 'cookie-name', value: 'cookie-value', path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -157,7 +110,9 @@ promise_test(async testCase => {
   const currentPath = currentUrl.pathname;
   const currentDirectory = currentPath.substr(0, currentPath.lastIndexOf('/'));
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: currentDirectory + '/' });
+      { name: 'cookie-name',
+        value: 'cookie-value',
+        path: currentDirectory + '/' });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
diff --git a/tests/wpt/web-platform-tests/cookie-store/cookieStore_set_arguments.tentative.https.any.js b/tests/wpt/web-platform-tests/cookie-store/cookieStore_set_arguments.tentative.https.any.js
index 528bc9de6c1..aab964d014e 100644
--- a/tests/wpt/web-platform-tests/cookie-store/cookieStore_set_arguments.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/cookie-store/cookieStore_set_arguments.tentative.https.any.js
@@ -28,18 +28,6 @@ promise_test(async testCase => {
   assert_equals(cookie.value, 'cookie-value');
 }, 'cookieStore.set with name and value in options');
 
-promise_test(async testCase => {
-  await cookieStore.delete('cookie-name');
-
-  cookieStore.set('cookie-name', 'cookie-value', { name: 'wrong-cookie-name' });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie.name, 'cookie-name');
-  assert_equals(cookie.value, 'cookie-value');
-}, 'cookieStore.set with name in both positional arguments and options');
-
 promise_test(async testCase => {
   await promise_rejects_js(testCase, TypeError,
       cookieStore.set('', 'suspicious-value=resembles-name-and-value'));
@@ -56,55 +44,15 @@ promise_test(async testCase => {
   assert_equals(cookie.value, 'suspicious-value=resembles-name-and-value');
 }, "cookieStore.set with normal name and an '=' in value");
 
-promise_test(async testCase => {
-  await cookieStore.delete('cookie-name');
-
-  cookieStore.set('cookie-name', 'cookie-value',
-                  { value: 'wrong-cookie-value' });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie.name, 'cookie-name');
-  assert_equals(cookie.value, 'cookie-value');
-}, 'cookieStore.set with value in both positional arguments and options');
-
 promise_test(async testCase => {
   const tenYears = 10 * 365 * 24 * 60 * 60 * 1000;
   const tenYearsFromNow = Date.now() + tenYears;
   await cookieStore.delete('cookie-name');
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { expires: tenYearsFromNow });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie.name, 'cookie-name');
-  assert_equals(cookie.value, 'cookie-value');
-}, 'cookieStore.set with expires set to a future timestamp');
-
-promise_test(async testCase => {
-  const tenYears = 10 * 365 * 24 * 60 * 60 * 1000;
-  const tenYearsAgo = Date.now() - tenYears;
-  await cookieStore.delete('cookie-name');
-
-  await cookieStore.set(
-      'cookie-name', 'cookie-value', { expires: tenYearsAgo });
-  testCase.add_cleanup(async () => {
-    await cookieStore.delete('cookie-name');
-  });
-  const cookie = await cookieStore.get('cookie-name');
-  assert_equals(cookie, null);
-}, 'cookieStore.set with expires set to a past timestamp');
-
-promise_test(async testCase => {
-  const tenYears = 10 * 365 * 24 * 60 * 60 * 1000;
-  const tenYearsFromNow = Date.now() + tenYears;
-  await cookieStore.delete('cookie-name');
-
-  await cookieStore.set(
-      'cookie-name', 'cookie-value', { expires: new Date(tenYearsFromNow) });
+      { name: 'cookie-name',
+        value: 'cookie-value',
+        expires: new Date(tenYearsFromNow) });
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
@@ -119,7 +67,9 @@ promise_test(async testCase => {
   await cookieStore.delete('cookie-name');
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { expires: new Date(tenYearsAgo) });
+      { name :'cookie-name',
+        value: 'cookie-value',
+        expires: new Date(tenYearsAgo) });
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
@@ -140,7 +90,7 @@ promise_test(async testCase => {
   const cookie = await cookieStore.get('cookie-name');
   assert_equals(cookie.name, 'cookie-name');
   assert_equals(cookie.value, 'cookie-value');
-}, 'cookieStore.set with name and value in options and expires in the future');
+}, 'cookieStore.set with expires set to a future timestamp');
 
 promise_test(async testCase => {
   const tenYears = 10 * 365 * 24 * 60 * 60 * 1000;
@@ -154,19 +104,21 @@ promise_test(async testCase => {
   });
   const cookie = await cookieStore.get('cookie-name');
   assert_equals(cookie, null);
-}, 'cookieStore.set with name and value in options and expires in the past');
+}, 'cookieStore.set with expires set to a past timestamp');
 
 promise_test(async testCase => {
   const currentUrl = new URL(self.location.href);
   const currentDomain = currentUrl.hostname;
 
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: `.${currentDomain}` }));
+      { name: 'cookie-name',
+        value: 'cookie-value',
+        domain: `.${currentDomain}` }));
 }, 'cookieStore.set domain starts with "."');
 
 promise_test(async testCase => {
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: 'example.com' }));
+      { name: 'cookie-name', value: 'cookie-value', domain: 'example.com' }));
 }, 'cookieStore.set with domain that is not equal current host');
 
 promise_test(async testCase => {
@@ -175,7 +127,7 @@ promise_test(async testCase => {
   await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: currentDomain });
+      { name: 'cookie-name', value: 'cookie-value', domain: currentDomain });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
   });
@@ -190,7 +142,7 @@ promise_test(async testCase => {
   const subDomain = `sub.${currentDomain}`;
 
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: subDomain }));
+      { name: 'cookie-name', value: 'cookie-value', domain: subDomain }));
   const cookie = await cookieStore.get('cookie-name');
   assert_equals(cookie, null);
 }, 'cookieStore.set with domain set to a subdomain of the current hostname');
@@ -203,7 +155,7 @@ promise_test(async testCase => {
   const domainSuffix = currentDomain.substr(1);
 
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { domain: domainSuffix }));
+      { name: 'cookie-name', value: 'cookie-value', domain: domainSuffix }));
   const cookie = await cookieStore.get('cookie-name');
   assert_equals(cookie, null);
 }, 'cookieStore.set with domain set to a non-domain-matching suffix of the ' +
@@ -218,8 +170,8 @@ promise_test(async testCase => {
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
-  await cookieStore.set('cookie-name', 'cookie-value2',
-                        { domain: currentDomain });
+  await cookieStore.set(
+      { name: 'cookie-name', value: 'cookie-value2', domain: currentDomain });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', domain: currentDomain });
   });
@@ -243,7 +195,7 @@ promise_test(async testCase => {
   await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: currentDirectory });
+      { name: 'cookie-name', value: 'cookie-value', path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -262,7 +214,7 @@ promise_test(async testCase => {
   await cookieStore.delete({ name: 'cookie-name', path: subDirectory });
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: subDirectory });
+      { name: 'cookie-name', value: 'cookie-value', path: subDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: subDirectory });
   });
@@ -277,7 +229,8 @@ promise_test(async testCase => {
   testCase.add_cleanup(async () => {
     await cookieStore.delete('cookie-name');
   });
-  await cookieStore.set('cookie-name', 'cookie-new-value', { path: '/' });
+  await cookieStore.set(
+      { name: 'cookie-name', value: 'cookie-new-value', path: '/' });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name',  path: '/' });
   });
@@ -295,7 +248,7 @@ promise_test(async testCase => {
   await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
 
   await cookieStore.set(
-      'cookie-name', 'cookie-value', { path: currentDirectory });
+      { name: 'cookie-name', value: 'cookie-value', path: currentDirectory });
   testCase.add_cleanup(async () => {
     await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
   });
@@ -313,7 +266,7 @@ promise_test(async testCase => {
   const invalidPath = currentDirectory.substr(1);
 
   await promise_rejects_js(testCase, TypeError, cookieStore.set(
-      'cookie-name', 'cookie-value', { path: invalidPath }));
+      { name: 'cookie-name', value: 'cookie-value', path: invalidPath }));
 }, 'cookieStore.set with path that does not start with /');
 
 promise_test(async testCase => {
diff --git a/tests/wpt/web-platform-tests/cookie-store/cookieStore_special_names.tentative.https.any.js b/tests/wpt/web-platform-tests/cookie-store/cookieStore_special_names.tentative.https.any.js
index 0cf4edc7543..db077478e0e 100644
--- a/tests/wpt/web-platform-tests/cookie-store/cookieStore_special_names.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/cookie-store/cookieStore_special_names.tentative.https.any.js
@@ -19,9 +19,8 @@
     // contexts, the set() should fail even if the expiration date makes
     // the operation a no-op.
     await cookieStore.set(
-      `${prefix}cookie-name`, `secure-cookie-value`, {
-        expires: Date.now() - (24 * 60 * 60 * 1000)
-      });
+        { name: `${prefix}cookie-name`, value: `secure-cookie-value`,
+          expires: Date.now() - (24 * 60 * 60 * 1000)});
     assert_equals(await cookieStore.get(`${prefix}cookie-name`), null);
     try { await cookieStore.delete(`${prefix}cookie-name`); } catch (e) {}
   }, `cookieStore.set of expired ${prefix} cookie name on secure origin`);
@@ -37,19 +36,18 @@ promise_test(async testCase => {
   const currentUrl = new URL(self.location.href);
   const currentDomain = currentUrl.hostname;
   await promise_rejects_js(testCase, TypeError,
-      cookieStore.set('__Host-cookie-name', 'cookie-value', {
-        domain: currentDomain
-      }));
+      cookieStore.set({ name: '__Host-cookie-name', value: 'cookie-value',
+                        domain: currentDomain }));
 }, 'cookieStore.set with __Host- prefix and a domain option');
 
 promise_test(async testCase => {
-  await cookieStore.set('__Host-cookie-name', 'cookie-value', { path: "/" });
+  await cookieStore.set({ name: '__Host-cookie-name', value: 'cookie-value',
+                          path: "/" });
 
   assert_equals(
       (await cookieStore.get(`__Host-cookie-name`)).value, "cookie-value");
 
   await promise_rejects_js(testCase, TypeError,
-      cookieStore.set('__Host-cookie-name', 'cookie-value', {
-        path: "/path"
-      }));
+      cookieStore.set( { name: '__Host-cookie-name', value: 'cookie-value',
+                         path: "/path" }));
 }, 'cookieStore.set with __Host- prefix a path option');
diff --git a/tests/wpt/web-platform-tests/css/css-break/float-inside-small-block.html b/tests/wpt/web-platform-tests/css/css-break/float-inside-small-block.html
new file mode 100644
index 00000000000..2afd6dacc9c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-break/float-inside-small-block.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://www.w3.org/TR/css-break-3/#parallel-flows">
+<link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div style="columns:2; column-fill:auto; column-gap:0; width:180px; height:100px; background:red;">
+  <div style="height:30px; background:green;"></div>
+  <div>
+    <div style="float:left; width:10px; height:170px; background:green;"></div>
+    <div style="height:30px; background:green;"></div>
+  </div>
+  <div style="height:40px; background:green;"></div>
+  <div style="height:100px; background:white;"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-ref.html
new file mode 100644
index 00000000000..e3e8b279ef6
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-ref.html
@@ -0,0 +1,17 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: container (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+</style>
+
+<div id=container></div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-child-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-child-ref.html
new file mode 100644
index 00000000000..229966a94b5
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-child-ref.html
@@ -0,0 +1,25 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: container with child and text (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-pos-children-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-pos-children-ref.html
new file mode 100644
index 00000000000..67b37e3a20d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/container-with-pos-children-ref.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: container with child and text (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  contain: layout;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.abspos { position: absolute; }
+.relpos { position: relative; }
+.fixedpos { position: fixed; }
+.start { top: 0; left: 0; }
+.mid { top: 10px; left: 10px; }
+.end { bottom: 0; right: 0; }
+.zindex { z-index: 1; }
+.small { width: 10px; height: 10px; background: blue; }
+.medium { width: 20px; height: 20px; background: green; }
+.large { width: 30px; height: 30px; background: pink; }
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+  <span>inline child</span>
+  <div class="abspos start small"></div>
+  <div class="relpos mid medium"></div>
+  <div class="fixedpos end large"></div>
+  <div class=relpos>
+    <div class="abspos mid small zindex"></div>
+  </div>
+</div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-001.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-001.html
new file mode 100644
index 00000000000..1c3eb90e3a7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-001.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden does not paint</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees are not painted">
+
+<style>
+#container {
+  content-visibility: hidden;
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.abspos { position: absolute; }
+.relpos { position: relative; }
+.fixedpos { position: fixed; }
+.start { top: 0; left: 0; }
+.mid { top: 10px; left: 10px; }
+.end { bottom: 0; right: 0; }
+.zindex { z-index: 1; }
+.small { width: 10px; height: 10px; background: blue; }
+.medium { width: 20px; height: 20px; background: green; }
+.large { width: 30px; height: 30px; background: pink; }
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+  <span>inline child</span>
+  <div class="abspos start small"></div>
+  <div class="relpos mid medium"></div>
+  <div class="fixedpos end large"></div>
+  <div class=relpos>
+    <div class="abspos mid small zindex"></div>
+  </div>
+</div>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-002.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-002.html
new file mode 100644
index 00000000000..75e02633f3a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-002.html
@@ -0,0 +1,42 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden starts painting when removed</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="content-visibility subtrees start painting when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003-ref.html
new file mode 100644
index 00000000000..6b2a227cde4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003-ref.html
@@ -0,0 +1,20 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden container is not breakable (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#parent {
+  width: 100px;
+}
+#container {
+  border-top: solid green 50px;
+  border-bottom: solid green 50px;
+}
+</style>
+
+<div id="parent">
+  <div id="container"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003.html
new file mode 100644
index 00000000000..08eb3a1288b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-003.html
@@ -0,0 +1,29 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden container is not breakable</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-003-ref.html">
+<meta name="assert" content="content-visibility container is not breakable">
+<script src="/common/reftest-wait.js"></script>
+<script src="resources/utils.js"></script>
+
+<style>
+#container {
+  border-top: solid green 50px;
+  border-bottom: solid green 50px;
+  content-visibility: hidden;
+}
+#parent {
+  columns: 2;
+  height: 0px;
+  width: 200px;
+  column-gap: 0;
+}
+</style>
+
+<div id="parent">
+  <div id="container">Text</div>
+</div>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004-ref.html
new file mode 100644
index 00000000000..5b094cdc5d8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004-ref.html
@@ -0,0 +1,9 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden container in an iframe (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<iframe></iframe>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004.html
new file mode 100644
index 00000000000..b02d0a82468
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-004.html
@@ -0,0 +1,20 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden container in an iframe</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-004-ref.html">
+<meta name="assert" content="content-visibility makes iframe contents hidden">
+
+<iframe id="frame" srcdoc='
+  <style>
+  #container {
+    width: 100px;
+    height: 100px;
+    content-visibility: hidden;
+  }
+  </style>
+  <div id="container">Lorem</div>
+'></iframe>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-005.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-005.html
new file mode 100644
index 00000000000..06e8eb89251
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-005.html
@@ -0,0 +1,42 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-006.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-006.html
new file mode 100644
index 00000000000..5c51a1fcd85
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-006.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (composited)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  will-change: transform;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-007.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-007.html
new file mode 100644
index 00000000000..087900e0b18
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-007.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+  will-change: transform;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-008.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-008.html
new file mode 100644
index 00000000000..40d7265aca4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-008.html
@@ -0,0 +1,44 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (composited with composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  will-change: transform;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+  will-change: transform;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-009.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-009.html
new file mode 100644
index 00000000000..30944e391dc
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-009.html
@@ -0,0 +1,47 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (positioned)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="positioned-container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.positioned {
+  position: absolute;
+  top: 0;
+  left: 0;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container class=positioned>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-010.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-010.html
new file mode 100644
index 00000000000..8d3f054ac10
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-010.html
@@ -0,0 +1,47 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (positioned child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.positioned {
+  position: absolute;
+  top: 0;
+  left: 0;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child class=positioned></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-011.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-011.html
new file mode 100644
index 00000000000..ea0decb06c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-011.html
@@ -0,0 +1,47 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden stops painting when added (positioned with a positioned child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="positioned-container-ref.html">
+<meta name="assert" content="content-visibility subtrees stop painting when hidden is added">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.positioned {
+  position: absolute;
+  top: 0;
+  left: 0;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container class=positioned>
+  Text.
+  <div id=child class=positioned></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-012.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-012.html
new file mode 100644
index 00000000000..fab0ded7c1a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-012.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden starts painting when removed (composited)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="content-visibility subtrees start painting when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  will-change: transform;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-013.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-013.html
new file mode 100644
index 00000000000..fc692ce17e7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-013.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden starts painting when removed (composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="content-visibility subtrees start painting when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+  will-change: transform;
+}
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-014.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-014.html
new file mode 100644
index 00000000000..b757c50c6c1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-014.html
@@ -0,0 +1,44 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden starts painting when removed (composited with a composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="content-visibility subtrees start painting when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  will-change: transform;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+  will-change: transform;
+}
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-015.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-015.html
new file mode 100644
index 00000000000..6099054ebd0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-015.html
@@ -0,0 +1,50 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hit testing</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden prevents hit-testing in the subtree">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+  padding: 0;
+}
+#outer {
+  width: 100px;
+  height: 100px;
+  background: lightblue;
+
+  content-visibility: hidden;
+}
+#inner {
+  margin: 25px;
+  width: 50px;
+  height: 50px;
+  background lightgreen;
+}
+</style>
+
+<body id="body">
+<div id="outer"><div id="inner"></div></div>
+</body>
+
+<script>
+async_test((t) => {
+  const container = document.getElementById("outer");
+
+  let target = document.elementFromPoint(50, 50);
+  t.step(() => assert_equals(target.id, "outer", "center hits outer"));
+  target = document.elementFromPoint(10, 50);
+  t.step(() => assert_equals(target.id, "outer", "edge hits outer"));
+  target = document.elementFromPoint(100, 50);
+  t.step(() => assert_equals(target.id, "body", "elsewhere hits body"));
+  t.done();
+});
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-016.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-016.html
new file mode 100644
index 00000000000..db3599e2435
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-016.html
@@ -0,0 +1,51 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hit testing (composited)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden prevents hit-testing in the subtree">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+  padding: 0;
+}
+#outer {
+  width: 100px;
+  height: 100px;
+  background: lightblue;
+
+  content-visibility: hidden;
+  will-change: transform;
+}
+#inner {
+  margin: 25px;
+  width: 50px;
+  height: 50px;
+  background lightgreen;
+}
+</style>
+
+<body id="body">
+<div id="outer"><div id="inner"></div></div>
+</body>
+
+<script>
+async_test((t) => {
+  const container = document.getElementById("outer");
+
+  let target = document.elementFromPoint(50, 50);
+  t.step(() => assert_equals(target.id, "outer", "center hits outer"));
+  target = document.elementFromPoint(10, 50);
+  t.step(() => assert_equals(target.id, "outer", "edge hits outer"));
+  target = document.elementFromPoint(100, 50);
+  t.step(() => assert_equals(target.id, "body", "elsewhere hits body"));
+  t.done();
+});
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-017.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-017.html
new file mode 100644
index 00000000000..a9c0e030096
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-017.html
@@ -0,0 +1,51 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hit testing (composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden prevents hit-testing in the subtree">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+  padding: 0;
+}
+#outer {
+  width: 100px;
+  height: 100px;
+  background: lightblue;
+
+  content-visibility: hidden;
+}
+#inner {
+  margin: 25px;
+  width: 50px;
+  height: 50px;
+  background lightgreen;
+  will-change: transform;
+}
+</style>
+
+<body id="body">
+<div id="outer"><div id="inner"></div></div>
+</body>
+
+<script>
+async_test((t) => {
+  const container = document.getElementById("outer");
+
+  let target = document.elementFromPoint(50, 50);
+  t.step(() => assert_equals(target.id, "outer", "center hits outer"));
+  target = document.elementFromPoint(10, 50);
+  t.step(() => assert_equals(target.id, "outer", "edge hits outer"));
+  target = document.elementFromPoint(100, 50);
+  t.step(() => assert_equals(target.id, "body", "elsewhere hits body"));
+  t.done();
+});
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-018.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-018.html
new file mode 100644
index 00000000000..15fe7f769d7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-018.html
@@ -0,0 +1,52 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hit testing (composited with a composited child)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden prevents hit-testing in the subtree">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+  padding: 0;
+}
+#outer {
+  width: 100px;
+  height: 100px;
+  background: lightblue;
+
+  content-visibility: hidden;
+  will-change: transform;
+}
+#inner {
+  margin: 25px;
+  width: 50px;
+  height: 50px;
+  background lightgreen;
+  will-change: transform;
+}
+</style>
+
+<body id="body">
+<div id="outer"><div id="inner"></div></div>
+</body>
+
+<script>
+async_test((t) => {
+  const container = document.getElementById("outer");
+
+  let target = document.elementFromPoint(50, 50);
+  t.step(() => assert_equals(target.id, "outer", "center hits outer"));
+  target = document.elementFromPoint(10, 50);
+  t.step(() => assert_equals(target.id, "outer", "edge hits outer"));
+  target = document.elementFromPoint(100, 50);
+  t.step(() => assert_equals(target.id, "body", "elsewhere hits body"));
+  t.done();
+});
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019-ref.html
new file mode 100644
index 00000000000..2ac2507faa1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019-ref.html
@@ -0,0 +1,16 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: iframe locking (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe id="frame" width=400 height=200 srcdoc=''></iframe>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019.sub.https.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019.sub.https.html
new file mode 100644
index 00000000000..9e91f474d0c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-019.sub.https.html
@@ -0,0 +1,36 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: cross-origin iframe locking</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-019-ref.html">
+<script src="/common/reftest-wait.js"></script>
+<script src="../resources/utils.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe id="frame" width=400 height=200 src='https://{{domains[www]}}:{{ports[https][0]}}/wpt_internal/display-lock/css-content-visibility/resources/frame.html'></iframe>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("frame").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020-ref.html
new file mode 100644
index 00000000000..3b59eab2138
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020-ref.html
@@ -0,0 +1,16 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe id="frame" width=400 height=200 srcdoc=''></iframe>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020.html
new file mode 100644
index 00000000000..6871a2a69d5
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-020.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-020-ref.html">
+<meta name="assert" content="content-visibility hidden iframe does not paint">
+
+<script src="/common/reftest-wait.js"></script>
+<script src="../resources/utils.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe id="frame" width=400 height=200 srcdoc='
+  <style>
+  div {
+    background: lightgreen;
+  }
+  </style>
+  <div>dolor sit amet</div>
+'></iframe>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("frame").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021-ref.html
new file mode 100644
index 00000000000..9b8b9953d39
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021-ref.html
@@ -0,0 +1,24 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden image (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+.myimg {
+  display: inline-block;
+  width: 400px;
+  height: 200px;
+  background: lightblue;
+  border: 1px solid black;
+}
+</style>
+
+<div>lorem ipsum</div>
+<div class="myimg"></div>
+<div class="myimg"></div>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021.html
new file mode 100644
index 00000000000..62f71396bc6
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-021.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden image</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-021-ref.html">
+<meta name="assert" content="content-visibility hidden img element does not paint replaced content">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+img {
+  width: 400px;
+  height: 200px;
+  background: lightblue;
+  border: 1px solid black;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<img id="img1" src="resources/dice.png"></img>
+<img id="img2" src="resources/circles.svg"></img>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("img1").classList.add("hidden");
+  document.getElementById("img2").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022-ref.html
new file mode 100644
index 00000000000..e6a2057a97f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022-ref.html
@@ -0,0 +1,23 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden svg (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+.mysvg {
+  display: inline-block;
+  width: 400px;
+  height: 300px;
+  background: lightblue;
+  border: 1px solid black;
+}
+</style>
+
+<div>lorem ipsum</div>
+<div class="mysvg"></div>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022.html
new file mode 100644
index 00000000000..01706898591
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-022.html
@@ -0,0 +1,52 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden svg</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-022-ref.html">
+<meta name="assert" content="content-visibility hidden svg does not paint">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+svg {
+  border: 1px solid black;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<svg xmlns="http://www.w3.org/2000/svg" width="400" height="300" viewBox="0 0 400 300" id="svg">
+  <g stroke-width="10" transform="translate(-30)">
+      <circle cx="80" cy="50" r="35" fill="#084" stroke="none"/>
+      <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="120" r="35" fill="#004" stroke="none"/>
+      <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="190" r="35" fill="#088" stroke="none"/>
+      <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="260" r="35" fill="#008" stroke="none"/>
+      <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+  </g>
+</svg>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("svg").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023-ref.html
new file mode 100644
index 00000000000..a789df868ab
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023-ref.html
@@ -0,0 +1,23 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe width=400 height=200 srcdoc='
+  <style>
+  div {
+    background: lightgreen;
+  }
+  </style>
+  <div>dolor sit amet</div>
+'></iframe>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023.html
new file mode 100644
index 00000000000..228db0380c4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-023.html
@@ -0,0 +1,44 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-023-ref.html">
+<meta name="assert" content="content-visibility hidden iframe paints when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<iframe id="frame" class=hidden width=400 height=200 srcdoc='
+  <style>
+  div {
+    background: lightgreen;
+  }
+  </style>
+  <div>dolor sit amet</div>
+'></iframe>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("frame").classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024-ref.html
new file mode 100644
index 00000000000..7e114c440bc
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024-ref.html
@@ -0,0 +1,23 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden image (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+img {
+  width: 400px;
+  height: 200px;
+  background: lightblue;
+  border: 1px solid black;
+}
+</style>
+
+<div>lorem ipsum</div>
+<img src="resources/dice.png"></img>
+<img src="resources/circles.svg"></img>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024.html
new file mode 100644
index 00000000000..4a63736e061
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-024.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden image</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-024-ref.html">
+<meta name="assert" content="content-visibility hidden img element paints when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+img {
+  width: 400px;
+  height: 200px;
+  background: lightblue;
+  border: 1px solid black;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<img id="img1" class=hidden src="resources/dice.png"></img>
+<img id="img2" class=hidden src="resources/circles.svg"></img>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("img1").classList.remove("hidden");
+  document.getElementById("img2").classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025-ref.html
new file mode 100644
index 00000000000..5f6855861c9
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025-ref.html
@@ -0,0 +1,31 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden svg (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+div {
+  background: blue;
+}
+svg {
+  border: 1px solid black;
+  background: lightblue;
+}
+</style>
+
+<div>lorem ipsum</div>
+<svg xmlns="http://www.w3.org/2000/svg" width="400" height="300" viewBox="0 0 400 300">
+  <g stroke-width="10" transform="translate(-30)">
+      <circle cx="80" cy="50" r="35" fill="#084" stroke="none"/>
+      <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="120" r="35" fill="#004" stroke="none"/>
+      <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="190" r="35" fill="#088" stroke="none"/>
+      <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="260" r="35" fill="#008" stroke="none"/>
+      <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+  </g>
+</svg>
+<div>consectetur adipiscing elit</div>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025.html
new file mode 100644
index 00000000000..03f50db8e54
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-025.html
@@ -0,0 +1,52 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden svg</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-025-ref.html">
+<meta name="assert" content="content-visibility hidden svg paints when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  background: blue;
+}
+svg {
+  border: 1px solid black;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>lorem ipsum</div>
+<svg class=hidden xmlns="http://www.w3.org/2000/svg" width="400" height="300" viewBox="0 0 400 300" id="svg">
+  <g stroke-width="10" transform="translate(-30)">
+      <circle cx="80" cy="50" r="35" fill="#084" stroke="none"/>
+      <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="120" r="35" fill="#004" stroke="none"/>
+      <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="190" r="35" fill="#088" stroke="none"/>
+      <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+      <circle cx="80" cy="260" r="35" fill="#008" stroke="none"/>
+      <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+  </g>
+</svg>
+<div>consectetur adipiscing elit</div>
+
+<script>
+async function runTest() {
+  document.getElementById("svg").classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(runTest);
+  });
+};
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-026.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-026.html
new file mode 100644
index 00000000000..d0815186edb
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-026.html
@@ -0,0 +1,87 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: containment added</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility visible does not add containment">
+<meta name="assert" content="content-visibility hidden adds containment">
+<meta name="assert" content="content-visibility auto adds containment">
+<meta name="assert" content="content-visibility auto visibility switches after rAF callbacks of the frame that produces the painted output">
+
+<style>
+.auto {
+  content-visibility: auto;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id="container"></div>
+<div id="async_container"></div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+function setUp(container) {
+  container.style = "";
+  container.classList = "";
+  assert_equals(getComputedStyle(container).contain, "none");
+}
+
+test(() => {
+  setUp(container);
+  container.classList.add("hidden");
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+}, "content-visibility: hidden adds contain: size layout style;");
+
+async_test((t) => {
+  setUp(async_container);
+  async_container.classList.add("auto");
+  t.step(() => assert_equals(getComputedStyle(async_container).contain, "size layout style paint"));
+  // Considering this as frame 1:
+  // At frame 2, the container has size-containment, and intersection
+  //   observations will be delivered at the end of that frame.
+  // At frame 3, the container still has size-containment, because visiblility
+  //   switch happens after rAF-callbacks have run.
+  // At frame 4, the container is no longer size-contained since it is visible.
+  requestAnimationFrame(() => {
+    // Frame 2 checks:
+    t.step(() => assert_equals(getComputedStyle(async_container).contain, "size layout style paint"));
+
+    requestAnimationFrame(() => {
+      // Frame 3 checks:
+      t.step(() => assert_equals(getComputedStyle(async_container).contain, "size layout style paint"));
+
+      requestAnimationFrame(() => {
+        // Frame 4 checks:
+        t.step(() => assert_equals(getComputedStyle(async_container).contain, "layout style paint"));
+        t.done();
+      });
+    });
+  });
+}, "content-visibility: auto adds contain: size layout style paint;");
+
+test(() => {
+  setUp(container);
+  container.classList.add("auto");
+  container.style = "contain: style;";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+  container.style = "contain: style layout;";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+  container.style = "";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+}, "content-visibility: auto adds contain: size layout style paint, can't be overridden");
+
+test(() => {
+  setUp(container);
+  container.classList.add("auto");
+  container.style = "contain: paint;";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+  container.style = "contain: strict;";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+  container.style = "contain: content;";
+  assert_equals(getComputedStyle(container).contain, "size layout style paint");
+}, "content-visibility keeps all containment even when shorthands are specified");
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027-ref.html
new file mode 100644
index 00000000000..ce40d529987
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027-ref.html
@@ -0,0 +1,17 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: auto in the viewport (reference).</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+.border {
+  border: 1px solid black;
+}
+</style>
+
+<div class=border>
+  Test passes if there is a border around this text.
+</div>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027.html
new file mode 100644
index 00000000000..912cefd815d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-027.html
@@ -0,0 +1,37 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: auto in the viewport.</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-027-ref.html">
+<meta name="assert" content="content-visibility auto element in the viewport paints">
+<meta name="assert" content="content-visibility auto element in the viewport does not have size containment">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+div {
+  content-visibility: auto;
+  border: 1px solid black;
+}
+</style>
+
+<div class=locked>
+  Test passes if there is a border around this text.
+</div>
+
+<script>
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      takeScreenshot();
+    });
+  });
+});
+
+</script>
+</html>
+
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-028.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-028.html
new file mode 100644
index 00000000000..1e48fb4fe3e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-028.html
@@ -0,0 +1,64 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<meta charset="utf-8">
+<title>Content Visibility: shadow dom</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="content-visibility hidden can be used in a shadow DOM">
+
+<script src="/common/reftest-wait.js"></script>
+<script src="resources/utils.js"></script>
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+.child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+<div id="host">
+  <div id="slotted">
+    Text.
+    <div class=child></div>
+  </div>
+</div>
+
+<script>
+async function runTest() {
+  // Set up hidden element within shadow root.
+  let shadowRoot = host.attachShadow({ mode: "open" });
+  let hidden = document.createElement("div");
+  shadowRoot.innerHTML = `
+    <style>
+    .container {
+      width: 150px;
+      height: 150px;
+      background: lightblue;
+    }
+    </style>`;
+  shadowRoot.appendChild(hidden);
+  hidden.innerHTML = "<slot></slot>";
+  hidden.getBoundingClientRect();
+  hidden.classList.add("container");
+  hidden.classList.add("hidden");
+  requestAnimationFrame(() => {
+    slotted.style = "display: none";
+    // Do a forced layout outside the hidden subtree.
+    host.getBoundingClientRect();
+
+    hidden.classList.remove("hidden");
+    slotted.style = "";
+    requestAnimationFrame(() => {
+      // Check that everything is painted as we expect.
+      takeScreenshot();
+    });
+  });
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-029.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-029.html
new file mode 100644
index 00000000000..75986346780
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-029.html
@@ -0,0 +1,27 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: innerText</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="innerText skips content-visibility hidden elements">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/utils.js"></script>
+
+This text should be visible.
+<div id="container" style="content-visibility: hidden">
+  This text should not be visible.
+  <div id="inner">
+    This text is also not visible.
+  </div>
+</div>
+
+<script>
+test(() => {
+  assert_equals(document.body.innerText, "This text should be visible.");
+  assert_equals(document.getElementById("inner").innerText, "");
+}, "innerText on locked element.");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-030.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-030.html
new file mode 100644
index 00000000000..397f8de519f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-030.html
@@ -0,0 +1,183 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: intersection observer interactions</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden is not intersecting from IO perspective">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+div {
+  width: 100px;
+  height: 100px;
+}
+#spacer {
+  height: 3000px;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div id="target1">
+  <div id="target2"></div>
+</div>
+<div id="target3">
+  <div id="target4"></div>
+</div>
+<div id="spacer"></div>
+<div id="find_me"></div>
+
+<script>
+async_test((t) => {
+  let target1, target2, target3, target4;
+  let observer;
+  let entries = [];
+
+  // Set everything up.
+  function enqueueStep1() {
+    target1 = document.getElementById("target1");
+    target2 = document.getElementById("target2");
+    target3 = document.getElementById("target3");
+    target4 = document.getElementById("target4");
+
+    observer = new IntersectionObserver((new_entries) => {
+      entries = entries.concat(new_entries);
+    });
+    observer.observe(target1);
+    observer.observe(target2);
+    observer.observe(target3);
+    observer.observe(target4);
+
+    entries = entries.concat(observer.takeRecords());
+    t.step(() => { assert_equals(entries.length, 0, "No initial notifications") });
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        runStep1();
+      });
+    });
+  }
+
+  // Verify that all elements are visible at the start, with intersection events.
+  function runStep1() {
+    const step = arguments.callee.name;
+    t.step(() => {
+      assert_equals(entries.length, 4, step);
+      // Clear the observed visible targets.
+      for (let i = 0; i < entries.length; ++i) {
+        assert_true(entries[i].isIntersecting);
+        assert_true(entries[i].target === target1 ||
+                    entries[i].target === target2 ||
+                    entries[i].target === target3 ||
+                    entries[i].target === target4, step);
+      }
+    });
+
+    entries = [];
+    enqueueStep2();
+  }
+
+  // Lock target3.
+  async function enqueueStep2() {
+    target3.classList.add("hidden");
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        runStep2();
+      });
+    });
+  }
+
+  // Verify that the hidden element received a not-intersecting event.
+  function runStep2() {
+    const step = arguments.callee.name;
+    t.step(() => {
+      assert_equals(entries.length, 1, step);
+      assert_false(entries[0].isIntersecting, step);
+      assert_equals(entries[0].target, target4, step);
+    });
+
+    entries = [];
+    enqueueStep3();
+  }
+
+  // Scroll all elements off screen.
+  function enqueueStep3() {
+    document.getElementById("find_me").scrollIntoView();
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        runStep3();
+      });
+    });
+  }
+
+  // Verify that all elements received not intersecting event, except
+  // target4, which was already not intersecting due to being hidden.
+  function runStep3() {
+    const step = arguments.callee.name;
+    t.step(() => {
+      assert_equals(entries.length, 3, step);
+      for (let i = 0; i < entries.length; ++i) {
+        assert_false(entries[i].isIntersecting, step);
+        assert_not_equals(entries[i].target, target4, step);
+      }
+    });
+
+    entries = [];
+    enqueueStep4();
+  }
+
+  // Scroll the elements back on screen.
+  function enqueueStep4() {
+    target1.scrollIntoView();
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        runStep4();
+      });
+    });
+  }
+
+  // Verify that all elements received not intersecting event, except
+  // target4, which remains not intersecting.
+  function runStep4() {
+    const step = arguments.callee.name;
+    t.step(() => {
+      assert_equals(entries.length, 3, step);
+      for (let i = 0; i < entries.length; ++i) {
+        assert_true(entries[i].isIntersecting);
+        assert_not_equals(entries[i].target, target4, step);
+      }
+    });
+
+    entries = [];
+    enqueueStep5();
+  }
+
+  // Unlock target3.
+  async function enqueueStep5() {
+    target3.classList.remove("hidden");
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        runStep5();
+      });
+    });
+  }
+
+  function runStep5() {
+    const step = arguments.callee.name;
+    t.step(() => {
+      assert_equals(entries.length, 1, step);
+      assert_true(entries[0].isIntersecting, step);
+      assert_equals(entries[0].target, target4, step);
+    });
+    t.done();
+  }
+
+
+  window.onload = () => {
+    requestAnimationFrame(enqueueStep1);
+  };
+}, "IntersectionObserver interactions");
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-031.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-031.html
new file mode 100644
index 00000000000..134b1c18f73
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-031.html
@@ -0,0 +1,76 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: resize observer interactions</title>
+<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden subtrees do not trigger resize observer">
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id="container">
+  <div id="resize" style="width: 50px; height: 50px">
+  </div>
+</div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+async_test((t) => {
+  let didCallback = false;
+
+  async function runTest() {
+    let resizeCallback = function (entries) {
+      didCallback = true;
+    }
+    let resizeObserver = new ResizeObserver(resizeCallback);
+
+    resizeObserver.observe(resize);
+
+    requestAnimationFrame(step2);
+  }
+
+  async function step2() {
+    assert_equals(true, didCallback, 'Resize observation should happen in first frame after registering');
+    didCallback = false;
+
+    const container = document.getElementById("container");
+    container.classList.add("hidden");
+
+    // Change the size of #resize. This should cause a resize observation, but
+    // only when the element becomes unhidden.
+    resize.style.width = '100px';
+
+    requestAnimationFrame(step3);
+  }
+
+  async function step3() {
+    assert_equals(false, didCallback,
+        'ResizeObsever should not run during while unrendered');
+    requestAnimationFrame(step4);
+  }
+
+  async function step4() {
+    assert_equals(false, didCallback,
+        'ResizeObsever should not run while unrendered');
+    const container = document.getElementById("container");
+    container.classList.remove("hidden");
+    requestAnimationFrame(step5);
+  }
+
+  async function step5() {
+    assert_equals(true, didCallback,
+        'ResizeObsevers should now run once becoming visible');
+    t.done();
+  }
+
+  window.onload = function() {
+    requestAnimationFrame(() => requestAnimationFrame(runTest));
+  };
+}, "ResizeObserver skipped while hidden");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032-ref.html
new file mode 100644
index 00000000000..0586f9b058f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032-ref.html
@@ -0,0 +1,10 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe, size changes (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<iframe width=200 height=300></iframe>
+</html>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032.html
new file mode 100644
index 00000000000..d3e5992d299
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-032.html
@@ -0,0 +1,26 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe, size changes</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-032-ref.html">
+<meta name="assert" content="content-visibility hidden iframes can change size.">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<iframe class=hidden id=frame width=200 height=200 srcdoc='Lorem ipsum'></iframe>
+
+<script>
+async function runTest() {
+  document.getElementById("frame").height = 300;
+  requestAnimationFrame(takeScreenshot);
+}
+
+onload = () => { requestAnimationFrame(runTest); };
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033-ref.html
new file mode 100644
index 00000000000..0586f9b058f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033-ref.html
@@ -0,0 +1,10 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden iframe, size changes (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<iframe width=200 height=300></iframe>
+</html>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033.sub.https.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033.sub.https.html
new file mode 100644
index 00000000000..93dba8eaf8d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-033.sub.https.html
@@ -0,0 +1,26 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Display Locking: locks an iframe, and changes its size</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-033-ref.html">
+<meta name="assert" content="content-visibility hidden cross origin iframe can change size">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<iframe id="frame" class=hidden width=200 height=200 src='https://{{domains[www]}}:{{ports[https][0]}}/wpt_internal/display-lock/css-content-visibility/resources/frame.html'></iframe>
+
+<script>
+async function runTest() {
+  document.getElementById("frame").height = 300;
+  requestAnimationFrame(takeScreenshot);
+}
+
+onload = () => { requestAnimationFrame(runTest); };
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034-ref.html
new file mode 100644
index 00000000000..79e03ee518e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034-ref.html
@@ -0,0 +1,29 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: hidden element shifted down (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  border: 1px solid blue;
+}
+#spacer {
+  width: 100px;
+  height: 100px;
+  background: lightgreen;
+}
+#checker {
+  width: 100px;
+  height: 50px;
+  background: green;
+}
+</style>
+
+<div id="spacer"></div>
+<div id="container"></div>
+<div id="checker"></div>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034.html
new file mode 100644
index 00000000000..9da2787deba
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-034.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden element shifted down</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-034-ref.html">
+<meta name="assert" content="content-visibility hidden element participates in layout">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  border: 1px solid blue;
+  content-visibility: hidden;
+}
+#spacer {
+  width: 100px;
+  height: 50px;
+  background: lightgreen;
+}
+#checker {
+  width: 100px;
+  height: 50px;
+  background: green;
+}
+</style>
+
+<div id="spacer"></div>
+<div id="container">Lorem</div>
+<div id="checker"></div>
+
+<script>
+function runTest() {
+  document.getElementById("spacer").style.height = "100px";
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => requestAnimationFrame(runTest));
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-035.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-035.html
new file mode 100644
index 00000000000..e7f922a0d34
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-035.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: hidden shadow descendant</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden element's subtree cannot be focused">
+<meta name="assert" content="content-visibility hidden element's subtree can access layout values">
+
+<div id="host">
+  <input id="slotted" type="text">
+</div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+let container = document.createElement("div");
+container.innerHTML = "<slot></slot>";
+
+let shadowRoot = host.attachShadow({ mode: "open" });
+shadowRoot.innerHTML = "<style>.hidden { content-visibility: hidden; }</style>";
+shadowRoot.appendChild(container);
+
+async_test((t) => {
+  async function focusTest() {
+    t.step(() => assert_not_equals(document.activeElement, slotted));
+    t.step(() => assert_not_equals(shadowRoot.activeElement, slotted));
+
+    container.classList.add("hidden");
+    requestAnimationFrame(() => {
+      t.step(() => assert_not_equals(document.activeElement, slotted));
+      t.step(() => assert_not_equals(shadowRoot.activeElement, slotted));
+
+      slotted.focus();
+      t.step(() => assert_not_equals(document.activeElement, slotted));
+      t.step(() => assert_not_equals(shadowRoot.activeElement, slotted));
+
+      forceLayoutTest();
+    });
+  }
+
+  async function forceLayoutTest() {
+    t.step(() => assert_equals(slotted.offsetTop, 0));
+    // Add a 20px div above the slotted div.
+    container.innerHTML = "<div style='height: 20px;'></div><slot></slot>";
+    t.step(() => assert_equals(slotted.offsetTop, 20));
+    t.done();
+  }
+
+  window.onload = function() {
+    requestAnimationFrame(() => requestAnimationFrame(focusTest));
+  };
+}, "Testing focus and force layout on element with hidden flat-tree ancestor");
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-036.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-036.html
new file mode 100644
index 00000000000..8dc56e91454
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-036.html
@@ -0,0 +1,61 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: style on hidden element & child</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="style is available for content-visibility hidden elements">
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id="container" class=hidden>
+  <div id="child">
+    <div id="grandchild"></div>
+  </div>
+</div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+async_test((t) => {
+  async function runTest() {
+    let container = document.getElementById("container");
+    container.style = "color: blue;";
+    t.step(() => assert_equals(getComputedStyle(container).color, "rgb(0, 0, 255)", "container color changed to blue"));
+    t.step(() => assert_equals(getComputedStyle(child).color, "rgb(0, 0, 255)", "child inherits blue color"));
+    t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(0, 0, 255)", "grandchild inherits blue color"));
+
+    child.style = "color: green;";
+    t.step(() => assert_equals(getComputedStyle(container).color, "rgb(0, 0, 255)", "container color is still blue"));
+    t.step(() => assert_equals(getComputedStyle(child).color, "rgb(0, 128, 0)", "child color changed to green"));
+    t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(0, 128, 0)", "grandchild inherits green color"));
+
+    child.style = "";
+
+    // Commit container, lock child.
+    container.classList.remove("hidden");
+    child.classList.add("hidden");
+    requestAnimationFrame(() => {
+      // Update style outside of the hidden subtree.
+      container.style = "color: red;";
+      container.offsetTop;
+
+      // Inheritance works as usual through hidden boundaries.
+      t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(255, 0, 0)", "grandchild inherits red color"));
+      t.step(() => assert_equals(getComputedStyle(child).color, "rgb(255, 0, 0)", "child inherits red color"));
+      t.step(() => assert_equals(getComputedStyle(container).color, "rgb(255, 0, 0)", "container color changed to red"));
+
+      t.done();
+    });
+  }
+
+  window.onload = function() {
+    requestAnimationFrame(() => requestAnimationFrame(runTest));
+  };
+}, "getComputedStyle gets up-to-date style");
+</script>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-037.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-037.html
new file mode 100644
index 00000000000..a2ce9221510
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-037.html
@@ -0,0 +1,39 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden grid with positioned child</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility hidden grid does not paint the subtree">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#grid {
+  display: grid;
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#positioned {
+  position: absolute;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div id=grid>
+  <div id=positioned>lorem ipsum</div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("grid").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => requestAnimationFrame(runTest);
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-038.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-038.html
new file mode 100644
index 00000000000..638a336c912
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-038.html
@@ -0,0 +1,107 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: measure layout</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden element layout is correct">
+<meta name="assert" content="content-visibility hidden element's subtree layout is correct">
+
+<style>
+#container {
+  background: lightgreen;
+  contain: layout;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#sizer {
+  width: 100px;
+  height: 100px;
+}
+.child {
+  width: 20px;
+  height: 20%;
+  background: cyan;
+}
+#spacer {
+  width: 150px;
+  height: 150px;
+  background: green;
+}
+</style>
+
+<div id="parent"></div>
+<div id="spacer"></div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+async_test((t) => {
+  function createChild(id) {
+    const child = document.createElement("div");
+    child.classList = "child";
+    child.id = id;
+    return child;
+  }
+
+  function measureForced() {
+    t.step(() => {
+      // Ensure children are laid out; this forces a layout if it wasn't done.
+      assert_equals(document.getElementById("0").offsetTop, 0, "0 forced");
+      assert_equals(document.getElementById("1").offsetTop, 20, "1 forced");
+      assert_equals(document.getElementById("2").offsetTop, 40, "2 forced");
+      // Both parent should be 0 height, since it's hidden. Both parent and spacers
+      // should have 8 offsetTop.
+      assert_equals(document.getElementById("parent").offsetTop, 8, "parent forced");
+      assert_equals(document.getElementById("spacer").offsetTop, 8, "spacer forced");
+    });
+  }
+
+  function measureWhenVisible() {
+    t.step(() => {
+      // Ensure children are still laid out.
+      assert_equals(document.getElementById("0").offsetTop, 0, "0 when visible");
+      assert_equals(document.getElementById("1").offsetTop, 20, "1 when visible");
+      assert_equals(document.getElementById("2").offsetTop, 40, "2 when visible");
+      // Now the parent should encompass a container, so spacer is pushed down.
+      assert_equals(document.getElementById("parent").offsetTop, 8, "parent when visible");
+      assert_equals(document.getElementById("spacer").offsetTop, 108, "spacer when visible");
+    });
+  }
+
+  function construct(container) {
+    const sizer = document.createElement("div");
+    sizer.id = "sizer";
+    container.appendChild(sizer);
+    sizer.appendChild(createChild("0"));
+    sizer.appendChild(createChild("1"));
+    sizer.appendChild(createChild("2"));
+  }
+
+  async function runTest() {
+    const container = document.createElement("div");
+    container.id = "container";
+
+    document.getElementById("parent").appendChild(container);
+    container.classList.add("hidden");
+    requestAnimationFrame(() => {
+      construct(container);
+      measureForced();
+
+      container.classList.remove("hidden");
+      requestAnimationFrame(() => requestAnimationFrame(() => {
+        measureWhenVisible();
+        t.done();
+      }));
+    });
+  }
+
+  window.onload = function() {
+    requestAnimationFrame(() => requestAnimationFrame(runTest));
+  };
+}, "Measure Forced Layout");
+</script>
+
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-039.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-039.html
new file mode 100644
index 00000000000..481dcc45831
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-039.html
@@ -0,0 +1,79 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: measure forced SVG text</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility hidden svg descendant has correct layout">
+
+<style>
+#container {
+  width: 100px;
+  height: 100px;
+  background: lightgreen;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div id="parent"></div>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+async_test((t) => {
+  let length;
+  function measureForced() {
+    t.step(() => {
+      length = document.getElementById("text").getComputedTextLength();
+      assert_not_equals(length, 0, "forced");
+
+    });
+  }
+
+  function measureWhenVisible() {
+    t.step(() => {
+      const visible_length = document.getElementById("text").getComputedTextLength();
+      assert_not_equals(visible_length, 0, "when visible");
+      assert_equals(visible_length, length, "when visible");
+    });
+  }
+
+  function construct(container) {
+    container.innerHTML = `
+      <svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
+        <style>
+          .t { font: 10px sans-serif; }
+        </style>
+        <text id="text" x="10" y="10" class="t">This is text</text>
+      </svg>
+    `;
+  }
+
+  async function runTest() {
+    const container = document.createElement("div");
+    container.id = "container";
+
+    document.getElementById("parent").appendChild(container);
+    container.classList.add("hidden");
+    requestAnimationFrame(() => {
+      construct(container);
+      measureForced();
+
+      container.classList.remove("hidden");
+      requestAnimationFrame(() => {
+        measureWhenVisible();
+        t.done();
+      });
+    });
+  }
+
+  window.onload = function() {
+    requestAnimationFrame(() => requestAnimationFrame(runTest));
+  };
+}, "Measure Forced SVG Text");
+</script>
+
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-040.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-040.html
new file mode 100644
index 00000000000..cf2e214e1a6
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-040.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Display Locking: absolute positioned in flex, which is in a hidden div.</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility hidden flex and abspos descendants don't paint">
+
+<script src="/common/reftest-wait.js"></script>
+<script src="resources/utils.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  position: relative;
+}
+div > div {
+  width: 100px;
+  height: 100px;
+  background: red;
+}
+.hidden {
+  content-visibility: hidden;
+}
+.flex { display: flex; }
+.abspos { position: absolute; }
+</style>
+
+<div id=container>
+  <div class=flex>
+    <div class=abspos></div>
+  </div>
+</div>
+
+<script>
+async function runTest() {
+  document.getElementById("container").classList.add("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => requestAnimationFrame(runTest));
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-041.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-041.html
new file mode 100644
index 00000000000..8d32a240c01
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-041.html
@@ -0,0 +1,42 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: pseudo elements</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="subtree-visiblity hidden doesn't paint ::before or ::after">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#container::before {
+  content: "a";
+  color: blue;
+}
+.hasAfter::after {
+  content: "b";
+  color: green;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id="log"></div>
+<div id="container" style="display:none;"></div>
+
+<script>
+async function runTest() {
+  container.classList.add("hasAfter");
+  container.classList.add("hidden");
+  container.style = "";
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042-ref.html
new file mode 100644
index 00000000000..ca33f5b6674
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042-ref.html
@@ -0,0 +1,20 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: pseudo elements</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container::before {
+  content: "a";
+  color: blue;
+}
+#container::after {
+  content: "b";
+  color: green;
+}
+</style>
+<div id="container"></div>
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042.html
new file mode 100644
index 00000000000..7dd9b998de5
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-042.html
@@ -0,0 +1,37 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: pseudo elements</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-042-ref.html">
+<meta name="assert" content="content-visibility elements paints ::before and ::after when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container::before {
+  content: "a";
+  color: blue;
+}
+.hasAfter::after {
+  content: "b";
+  color: green;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id="container" class=hidden style="display:none;"></div>
+
+<script>
+async function runTest() {
+  container.classList.add("hasAfter");
+  container.classList.remove("hidden");
+  container.style = "";
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-043.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-043.html
new file mode 100644
index 00000000000..4787e03fef0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-043.html
@@ -0,0 +1,40 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: scroll child into view, and adopt to a document</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="scrollIntoView on a hidden subtree is a no-op">
+<meta name="assert" content="adopting an element in a hidden subtree works (no asserts / crashes)">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function moveChild() {
+  child.scrollIntoView();
+  document.implementation.createDocument( "", null).adoptNode(child);
+  requestAnimationFrame(takeScreenshot);
+}
+
+async function runTest() {
+  requestAnimationFrame(moveChild);
+}
+
+window.onload = requestAnimationFrame(runTest);
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-044.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-044.html
new file mode 100644
index 00000000000..bf4f6168d41
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-044.html
@@ -0,0 +1,32 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: slot moved after container is hidden</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="ensure that hidden slotted element can be updated">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id=host>
+<input id=slotted>
+<script>
+
+async_test((t) => {
+  let container = document.createElement("div");
+  container.innerHTML = "<slot></slot>";
+  let shadowRoot = host.attachShadow({ mode: "open" });
+  shadowRoot.innerHTML = "<style>.hidden { content-visibility: hidden }</style>";
+  shadowRoot.appendChild(container);
+
+  t.step(async () => {
+    container.classList.add("hidden");
+    requestAnimationFrame(() => {
+      assert_equals(slotted.offsetTop, 0);
+      container.innerHTML = "<div style='height: 20px;'></div><slot></slot>";
+      t.done();
+    });
+  });
+});
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-045.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-045.html
new file mode 100644
index 00000000000..0809dda14a8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-045.html
@@ -0,0 +1,52 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: auto subtree becomes hidden in the viewport</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="hidden subtree because auto and so stops painting">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.auto { content-visibility: auto; }
+.hidden { content-visibility: hidden; }
+
+</style>
+
+<div id=container class=auto>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+
+function runTest() {
+  document.getElementById("container").classList.remove("auto");
+  document.getElementById("container").classList.add("hidden");
+
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+
+</script>
+</html>
+
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-046.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-046.html
new file mode 100644
index 00000000000..4d3875270e7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-046.html
@@ -0,0 +1,45 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: viewport auto painting.</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="viewport intersection paints the content-visibility auto element">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div id=container class=auto>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+
+function runTest() {
+  document.getElementById("target").classList.add("auto");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(
+  () => requestAnimationFrame(takeScreenshot));
+
+</script>
+</html>
+
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-047.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-047.html
new file mode 100644
index 00000000000..8a3cde252f0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-047.html
@@ -0,0 +1,49 @@
+<!doctype HTML>
+<meta charset="utf8">
+<title>Content Visibility: tab order navigation ignores hidden subtrees</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="tab order navigation ignores hidden subtrees.">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+
+<style>
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<input id=one type=text></input>
+<div class=hidden>
+  <input id=two type=text></input>
+  <input id=three type=text></input>
+  <input id=four type=text></input>
+</div>
+<input id=five type=text></input>
+
+<script>
+async_test((t) => {
+  const tab = "\t";
+  async function step1() {
+    await test_driver.send_keys(document.body, tab);
+    t.step(() => {
+      assert_equals(document.activeElement, document.getElementById("one"));
+    });
+    requestAnimationFrame(step2);
+  }
+
+  async function step2() {
+    await test_driver.send_keys(document.body, tab);
+    t.step(() => {
+      assert_equals(document.activeElement, document.getElementById("five"));
+    });
+    t.done();
+  }
+
+  window.onload = () => { requestAnimationFrame(step1); };
+}, "Tab order navigation skips hidden subtrees");
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-048.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-048.html
new file mode 100644
index 00000000000..2b8679b5dd6
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-048.html
@@ -0,0 +1,46 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: navigating to a text fragment.</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="timeout" content="long">
+<meta name="assert" content="content-visibility: auto subtrees are 'searchable' by text fragment links">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/scroll-to-text-fragment/stash.js"></script>
+
+<script>
+promise_test(t => new Promise((resolve, reject) => {
+    const fragment = '#:~:text=hiddentext';
+    const key = token();
+    test_driver.bless("Open a URL with a text fragment directive", () => {
+      window.open(`resources/text-fragment-target-auto.html?key=${key}${fragment}`,
+                  '_blank',
+                  'noopener');
+    });
+    fetchResults(key, resolve, reject);
+}).then(data => {
+  assert_equals(data.scrollPosition, "text");
+  assert_equals(data.target, "text");
+}), "Fragment navigation with content-visibility; single text");
+
+promise_test(t => new Promise((resolve, reject) => {
+    const fragment = '#:~:text=start,end';
+    const key = token();
+    test_driver.bless("Open a URL with a text fragment directive", () => {
+      window.open(`resources/text-fragment-target-auto.html?key=${key}${fragment}`,
+                  '_blank',
+                  'noopener');
+    });
+    fetchResults(key, resolve, reject);
+}).then(data => {
+  assert_equals(data.scrollPosition, "text2");
+  assert_equals(data.target, "text2and3ancestor");
+}), "Fragment navigation with content-visibility; range across blocks");
+</script>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049-ref.html
new file mode 100644
index 00000000000..be5fd78a341
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049-ref.html
@@ -0,0 +1,33 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: anchor links paint subtrees (reference)</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  contain: style layout;
+  width: 150px;
+  height: 150px;
+  background: lightgreen;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background: green;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"><div id="target"></div></div>
+
+<script>
+target.scrollIntoView();
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049.html
new file mode 100644
index 00000000000..f130d77b665
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-049.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: anchor links paint subtrees</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-049-ref.html">
+<meta name="assert" content="content-visibility auto subtrees respond to anchor links">
+
+<script src="/common/reftest-wait.js"></script>
+<script src="../resources/utils.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightgreen;
+  content-visibility: auto;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background: green;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"><div id="target"></div></div>
+
+<script>
+function runTest() {
+  location.href += "#target";
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => { requestAnimationFrame(runTest); };
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-050.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-050.html
new file mode 100644
index 00000000000..bcc4f5e430c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-050.html
@@ -0,0 +1,39 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: focus on new element</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="focus can target content-visibility: auto subtrees created while hidden">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+.auto {
+  content-visibility: auto;
+}
+.spacer {
+  height: 3000px;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=auto></div>
+
+<script>
+async_test((t) => {
+  function runTest() {
+    const focusable = document.createElement("div");
+    focusable.tabIndex = 0;
+    container.appendChild(focusable);
+    focusable.focus();
+    requestAnimationFrame(() => {
+      t.step(() => assert_greater_than(document.scrollingElement.scrollTop, 500));
+      t.done();
+    });
+  }
+  onload = requestAnimationFrame(() => requestAnimationFrame(runTest));
+}, "Using tabindex to focus an newly constructed element in an auto subtree focuses element");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-051.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-051.html
new file mode 100644
index 00000000000..d85d6a4b005
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-051.html
@@ -0,0 +1,44 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: switching to block stop painting</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-ref.html">
+<meta name="assert" content="content-visibility has no effect on non-atomic inlines, but switching to block stop painting">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  content-visibility: hidden;
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.inline {
+  display: inline;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container class=inline>
+  Text.
+  <div id=child></div>
+  <span>inline child</span>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("inline");
+  takeScreenshot();
+}
+
+window.onload = () => requestAnimationFrame(runTest);
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-052.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-052.html
new file mode 100644
index 00000000000..b6a1c29a260
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-052.html
@@ -0,0 +1,60 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden starts painting when removed</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-pos-children-ref.html">
+<meta name="assert" content="content-visibility subtrees start painting when hidden is removed">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  contain: layout;
+}
+.hidden {
+  content-visibility: hidden;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.abspos { position: absolute; }
+.relpos { position: relative; }
+.fixedpos { position: fixed; }
+.start { top: 0; left: 0; }
+.mid { top: 10px; left: 10px; }
+.end { bottom: 0; right: 0; }
+.zindex { z-index: 1; }
+.small { width: 10px; height: 10px; background: blue; }
+.medium { width: 20px; height: 20px; background: green; }
+.large { width: 30px; height: 30px; background: pink; }
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+  <span>inline child</span>
+  <div class="abspos start small"></div>
+  <div class="relpos mid medium"></div>
+  <div class="fixedpos end large"></div>
+  <div class=relpos>
+    <div class="abspos mid small zindex"></div>
+  </div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.remove("hidden");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = runTest;
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-053.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-053.html
new file mode 100644
index 00000000000..ebdaecbc62b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-053.html
@@ -0,0 +1,30 @@
+<html>
+<meta charset="utf8">
+<title>Content Visibility: focus on display none element</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="tab navigation skips display none elements in an auto subtree">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id=spacer style="height: 3000px"></div>
+<div id="host">
+  <input id="slotted" type="text">
+</div>
+
+<script>
+test(() => {
+  const container = document.createElement("div");
+  container.innerHTML = "<slot></slot>";
+  container.style = "content-visibility: auto";
+
+  const shadowRoot = host.attachShadow({ mode: "open" });
+  shadowRoot.appendChild(container);
+
+  assert_not_equals(document.activeElement, slotted);
+  slotted.focus();
+  assert_equals(document.activeElement, slotted);
+}, "Targetting a slotted auto-hidden element with focus makes it the active element");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-054.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-054.html
new file mode 100644
index 00000000000..232dc0d7b11
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-054.html
@@ -0,0 +1,34 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: focus on styled element</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="focus does not target display-none but hidden elements">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="container" style="content-visibility: auto">
+  <div id="focusable1" tabIndex="0">
+    focusable thing
+  </div>
+  <div id="displayNoneParent">
+    <div id="focusable2" tabIndex="0">
+      focusable thing
+    </div>
+  </div>
+</div>
+
+<script>
+test(() => {
+  focusable1.style.display = "none";
+  focusable1.focus();
+  assert_not_equals(document.activeElement, focusable1);
+
+  displayNoneParent.style.display = "none";
+  focusable2.focus();
+  assert_not_equals(document.activeElement, focusable2);
+}, "Trying to focus on an element in a hidden subtree with display none will not work");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-055.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-055.html
new file mode 100644
index 00000000000..a53f4bc7e26
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-055.html
@@ -0,0 +1,42 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: anchor links prevented</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-scrolled-ref.html">
+<meta name="assert" content="anchor link scroll is not prevented when the target is hidden">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightgreen;
+  content-visibility: hidden;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background: green;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"><div id="target"></div></div>
+
+<script>
+function runTest() {
+  location.href += "#target";
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => { requestAnimationFrame(runTest); };
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-056.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-056.html
new file mode 100644
index 00000000000..4c12d2bf2a7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-056.html
@@ -0,0 +1,42 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: scrollIntoView prevented</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-scrolled-ref.html">
+<meta name="assert" content="scrollIntoView is not prevented when the target is hidden">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightgreen;
+  content-visibility: hidden;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background: green;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"><div id="target"></div></div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = () => { requestAnimationFrame(runTest); };
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-057.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-057.html
new file mode 100644
index 00000000000..083cebf9020
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-057.html
@@ -0,0 +1,52 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: hidden subtree becomes auto in the viewport</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="container-with-child-ref.html">
+<meta name="assert" content="hidden subtree because auto and then paints">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+.auto { content-visibility: auto; }
+.hidden { content-visibility: hidden; }
+
+</style>
+
+<div id=container class=hidden>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+
+function runTest() {
+  document.getElementById("container").classList.remove("hidden");
+  document.getElementById("container").classList.add("auto");
+
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+
+</script>
+</html>
+
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058-ref.html
new file mode 100644
index 00000000000..067d064ca72
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058-ref.html
@@ -0,0 +1,60 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto, scrollIntoView() (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  height: 10000px;
+}
+.container {
+  position: relative;
+  width: 150px;
+  background: lightblue;
+  contain-intrinsic-size: 50px 250px;
+}
+.size_contained {
+  contain: size;
+}
+.child {
+  width: 50px;
+  height: 300px;
+  background: lightgreen;
+}
+#target {
+  position: absolute;
+  bottom: 0;
+
+  width: 10px;
+  height: 10px;
+  background: blue;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class="container size_contained">
+  <div class=child></div>
+  <div id=target></div>
+</div>
+<div class=spacer></div>
+
+<script>
+
+function runReference() {
+  document.getElementById("target").scrollIntoView(true /* alignToTop */);
+  document.getElementById("container").classList.remove("size_contained");
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runReference();
+    });
+  });
+});
+
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058.html
new file mode 100644
index 00000000000..41353c96d72
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-058.html
@@ -0,0 +1,63 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>Content Visibility: auto, scrollIntoView()</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-058-ref.html">
+<meta name="assert" content="scrollIntoView() uses contain:size information to find target offset">
+<meta name="assert" content="viewport intersection removes contain:size thus moving target">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  height: 10000px;
+}
+.container {
+  width: 150px;
+  background: lightblue;
+  contain-intrinsic-size: 50px 250px;
+}
+.child {
+  width: 50px;
+  height: 300px;
+  background: lightgreen;
+}
+#target {
+  position: absolute;
+  bottom: 0;
+
+  width: 10px;
+  height: 10px;
+  background: blue;
+}
+.auto { content-visibility: auto; }
+
+</style>
+
+<div class=spacer></div>
+<div class="container auto">
+  <div class=child></div>
+  <div id=target></div>
+</div>
+<div class=spacer></div>
+
+<script>
+
+function runTest() {
+  document.getElementById("target").scrollIntoView(true /* alignToTop */);
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+
+</script>
+</html>
+
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059-ref.html
new file mode 100644
index 00000000000..bb086ad6087
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059-ref.html
@@ -0,0 +1,40 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + scrollIntoView (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+.spacer {
+  height: 1000px;
+  background: lightgreen;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  position: relative;
+  top: 75px;
+  visibility: hidden;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+</style>
+
+<div>top of the page</div>
+<div class=spacer></div>
+<div id=container>
+  <div id=target></div>
+</div>
+<div class=spacer></div>
+<div>bottom of the page</div>
+
+<script>
+onload = () => document.getElementById("target").scrollIntoView();
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059.html
new file mode 100644
index 00000000000..1242a5b55a0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-059.html
@@ -0,0 +1,58 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + scrollIntoView</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-059-ref.html">
+<meta name="assert" content="scrollIntoView scrolls to element under hidden, not just container">
+<meta name="assert" content="scrollIntoView does not start painting hidden content">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  height: 1000px;
+  background: lightgreen;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div>top of the page</div>
+<div class=spacer></div>
+<div id=container class=hidden>
+  <div id=target></div>
+</div>
+<div class=spacer></div>
+<div>bottom of the page</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-060.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-060.html
new file mode 100644
index 00000000000..25c48214881
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-060.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + scrollIntoView on display:none</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="scrollIntoView ignores display:none element in a hidden subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: none;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=hidden>
+  <div id=target></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-061.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-061.html
new file mode 100644
index 00000000000..49d86d63005
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-061.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + scrollIntoView on display:contents</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="scrollIntoView ignores display:contents element in a hidden subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: contents;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=hidden>
+  <div id=target></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-062.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-062.html
new file mode 100644
index 00000000000..8677daa6d44
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-062.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto + scrollIntoView on display:none</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="scrollIntoView ignores display:none element in an auto subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: none;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=auto>
+  <div id=target></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-063.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-063.html
new file mode 100644
index 00000000000..9466b63a892
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-063.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto + scrollIntoView on display:contents</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="scrollIntoView ignores display:contents element in an auto subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: contents;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=auto>
+  <div id=target></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").scrollIntoView();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064-ref.html
new file mode 100644
index 00000000000..b2232a4a725
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064-ref.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + scrollIntoView (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  height: 1000px;
+  background: lightgreen;
+}
+#container {
+  position: relative;
+  width: 150px;
+  background: lightblue;
+  contain: paint;
+}
+#child {
+  width: 150px;
+  height: 300px;
+}
+#target {
+  position: absolute;
+  bottom: 0;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+</style>
+
+<div>top of the page</div>
+<div class=spacer></div>
+<div id=container>
+  <div id=child></div>
+  <div id=target tabindex=0></div>
+</div>
+<div class=spacer></div>
+<div>bottom of the page</div>
+
+<script>
+function runReference() {
+  document.getElementById("target").focus();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runReference();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064.html
new file mode 100644
index 00000000000..d3662db4169
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-064.html
@@ -0,0 +1,63 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto + focus</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="content-visibility-064-ref.html">
+<meta name="assert" content="focus() can focus auto skipped subtree elements">
+<meta name="assert" content="focus() scrolls after removing contain:size">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  height: 1000px;
+  background: lightgreen;
+}
+#container {
+  width: 150px;
+  background: lightblue;
+  contain-intrinsic-size: 50px 150px;
+}
+#child {
+  width: 150px;
+  height: 300px;
+}
+#target {
+  position: absolute;
+  bottom: 0;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div>top of the page</div>
+<div class=spacer></div>
+<div id=container class=auto>
+  <div id=child></div>
+  <div id=target tabindex=0></div>
+</div>
+<div class=spacer></div>
+<div>bottom of the page</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").focus();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-065.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-065.html
new file mode 100644
index 00000000000..a7dcaf32804
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-065.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto + focus on display:none</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="focus ignores display:none element in an auto subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: none;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=auto>
+  <div id=target tabindex=0></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").focus();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-066.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-066.html
new file mode 100644
index 00000000000..a963976943b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-066.html
@@ -0,0 +1,57 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: auto + focus on display:contents</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="focus ignores display:contents element in an auto subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  display: contents;
+
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.auto {
+  content-visibility: auto;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=auto>
+  <div id=target tabindex=0></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").focus();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-067.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-067.html
new file mode 100644
index 00000000000..994f418364f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-067.html
@@ -0,0 +1,55 @@
+<!doctype HTML>
+
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: hidden + focus</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="spacer-and-container-ref.html">
+<meta name="assert" content="focus ignores element in a hidden subtree">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+#target {
+  position: relative;
+  top: 75px;
+
+  width: 50px;
+  height: 50px;
+  background: red;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container class=hidden>
+  <div id=target tabindex=0></div>
+</div>
+
+<script>
+function runTest() {
+  document.getElementById("target").focus();
+  requestAnimationFrame(takeScreenshot);
+}
+
+window.onload = requestAnimationFrame(() => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      runTest();
+    });
+  });
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-068.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-068.html
new file mode 100644
index 00000000000..330256adb29
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-068.html
@@ -0,0 +1,98 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: off-screen focus</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility auto element remains non-skipped when elements in its subtree have focus.">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body, html {
+  padding: 0;
+  margin: 0;
+}
+
+.spacer {
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  background: lightgreen;
+  contain-intrinsic-size: 50px 100px;
+  content-visibility: auto;
+}
+#focusable {
+  width: 10px;
+  height: 10px;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container>
+  <div id=focusable tabindex=0></div>
+</div>
+<div class=spacer></div>
+
+<script>
+async_test((t) => {
+  // Initially container should be 3000px offscreen with contained height 100px.
+  function step1() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step1 offset");
+      assert_equals(r.height, 100, "step1 height");
+    });
+
+    focusable.focus();
+    requestAnimationFrame(step2);
+  }
+  // After focusing the subtree, the container should be somewhere closer than
+  // 3000px (scrolled into view) and the height should be 10px, since it no
+  // longer has containment.
+  function step2() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_less_than(r.y, 3000, "step2 offset");
+      assert_equals(r.height, 10, "step2 height");
+    });
+    document.scrollingElement.scrollTop = 0;
+    requestAnimationFrame(step3);
+  }
+  // After scrolling the document back to the top, the container should be back
+  // at 3000px but because its subtree is still focused, it should have height
+  // 10px.
+  function step3() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step3 offset");
+      assert_equals(r.height, 10, "step3 height");
+    });
+    requestAnimationFrame(step4);
+  }
+  // This is a repeat of step3, to ensure that this is a stable state.
+  function step4() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step4 offset");
+      assert_equals(r.height, 10, "step4 height");
+    });
+    focusable.blur();
+    requestAnimationFrame(step5);
+  }
+  // After blurring the focused element, we should go back to the contained
+  // height of 100px.
+  function step5() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step5 offset");
+      assert_equals(r.height, 100, "step5 height");
+    });
+    t.done();
+  }
+  step1();
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-069.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-069.html
new file mode 100644
index 00000000000..89cbd1dc93b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-069.html
@@ -0,0 +1,53 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: pending visibility changes</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="disconnecting elements while visibility state adjustments are pending does not crash">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+  padding: 0;
+}
+.spacer {
+  height: 3000px;
+}
+.auto {
+  content-visibility: auto;
+  width: 5px;
+  height: 5px;
+}
+</style>
+
+<body id="body">
+<div id=one class=auto>text</div>
+<div class=spacer></div>
+<div id=two class=auto>text</div>
+<div class=spacer></div>
+</body>
+
+<script>
+async_test((t) => {
+  function runTest() {
+    document.scrollingElement.scrollTop = 2990;
+
+    const range = document.createRange();
+    range.selectNodeContents(one);
+    window.getSelection().addRange(range);
+
+    requestAnimationFrame(() => {
+      one.remove();
+      two.remove();
+      t.done();
+    });
+  }
+  onload = requestAnimationFrame(() => requestAnimationFrame(runTest));
+});
+
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-070.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-070.html
new file mode 100644
index 00000000000..4f63069edde
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-070.html
@@ -0,0 +1,112 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: off-screen selection</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility auto element remains non-skipped when elements in its subtree have selection.">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body, html {
+  padding: 0;
+  margin: 0;
+}
+
+.spacer {
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  background: lightgreen;
+  contain-intrinsic-size: 50px 100px;
+  content-visibility: auto;
+}
+#selectable {
+  width: 10px;
+  height: 10px;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container>
+  <div id=selectable>hello</div>
+</div>
+<div class=spacer></div>
+
+<script>
+async_test((t) => {
+  const selection = window.getSelection();
+  const range = document.createRange();
+  range.selectNodeContents(selectable);
+
+  // Initially container should be 3000px offscreen with contained height 100px.
+  function step1() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step1 offset");
+      assert_equals(r.height, 100, "step1 height");
+    });
+
+    selection.removeAllRanges();
+    selection.addRange(range);
+
+    requestAnimationFrame(step2);
+  }
+  // The container has a selection so it should be smaller now, height 10px.
+  function step2() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step3 offset");
+      assert_equals(r.height, 10, "step3 height");
+    });
+    document.scrollingElement.scrollTop = 3000;
+    requestAnimationFrame(step3);
+  }
+  // After scrolling the container should be closer and still height 10px.
+  function step3() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_less_than(r.y, 3000, "step2 offset");
+      assert_equals(r.height, 10, "step2 height");
+    });
+    document.scrollingElement.scrollTop = 0;
+    requestAnimationFrame(step4);
+  }
+  // Scrolling back to the top we should remain at height 10px.
+  function step4() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step4 offset");
+      assert_equals(r.height, 10, "step4 height");
+    });
+    requestAnimationFrame(step5);
+  }
+  // Repeat step4 to ensure we're in a stable situation.
+  function step5() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step4 offset");
+      assert_equals(r.height, 10, "step4 height");
+    });
+
+    selection.removeAllRanges();
+
+    requestAnimationFrame(step6);
+  }
+  // After removing the selection we should go back to the contained
+  // height of 100px.
+  function step6() {
+    const r = container.getBoundingClientRect();
+    t.step(() => {
+      assert_equals(r.y, 3000, "step5 offset");
+      assert_equals(r.height, 100, "step5 height");
+    });
+    t.done();
+  }
+  step1();
+});
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-071.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-071.html
new file mode 100644
index 00000000000..6f267b27c7e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-071.html
@@ -0,0 +1,185 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: off-screen selection</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility auto element remains non-skipped when elements in its subtree have selection.">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body, html {
+  padding: 0;
+  margin: 0;
+}
+
+.spacer {
+  height: 3000px;
+}
+.container {
+  width: 10px;
+  contain-intrinsic-size: 10px 20px;
+  content-visibility: auto;
+}
+.child {
+  width: 10px;
+  height: 10px;
+}
+</style>
+
+<div class=spacer></div>
+<div id=container_1 class=container><div id=child_1 class=child>hello</div></div>
+<div id=container_2 class=container><div id=child_2 class=child>hello</div></div>
+<div id=container_3 class=container><div id=child_3 class=child>hello</div></div>
+<div id=container_4 class=container><div id=child_4 class=child>hello</div></div>
+<div id=container_5 class=container><div id=child_5 class=child>hello</div></div>
+
+<script>
+function isLocked(container) {
+  const height = container.getBoundingClientRect().height;
+  assert_true(height == 20 || height == 10);
+  return container.getBoundingClientRect().height == 20;
+}
+
+const selection = window.getSelection();
+function resetSelection() {
+  selection.removeAllRanges();
+  assert_true(isLocked(container_1));
+  assert_true(isLocked(container_2));
+  assert_true(isLocked(container_3));
+  assert_true(isLocked(container_4));
+  assert_true(isLocked(container_5));
+}
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.selectNodeContents(child_2);
+  selection.addRange(range);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_true(isLocked(container_3), "3");
+  assert_true(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+}, "One elements selected: ");
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.selectNodeContents(child_2);
+  selection.addRange(range);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_true(isLocked(container_3), "3");
+  assert_true(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+
+  selection.extend(child_4, 0);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_false(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+}, "Range extended to cover more elements: ");
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.setStart(child_2, 0);
+  range.setEnd(child_4, 0);
+  selection.addRange(range);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_false(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+
+  selection.extend(child_2, 1);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_true(isLocked(container_3), "3");
+  assert_true(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+}, "Range shrunk to cover fewer elements: ");
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.setStart(child_3, 0);
+  range.setEnd(child_3, 0);
+  selection.addRange(range);
+  selection.extend(child_2, 0);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_true(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+
+  selection.extend(child_4, 0);
+
+  assert_true(isLocked(container_1), "1");
+  assert_true(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_false(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+}, "Range flipped from back to front: ");
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.setStart(child_3, 0);
+  range.setEnd(child_4, 0);
+  selection.addRange(range);
+
+  assert_true(isLocked(container_1), "1");
+  assert_true(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_false(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+
+  selection.extend(child_2, 0);
+
+  assert_true(isLocked(container_1), "1");
+  assert_false(isLocked(container_2), "2");
+  assert_false(isLocked(container_3), "3");
+  assert_true(isLocked(container_4), "4");
+  assert_true(isLocked(container_5), "5");
+}, "Range flipped from front to back: ");
+
+test(() => {
+  resetSelection();
+  const range = document.createRange();
+  range.setStart(child_1, 0);
+  range.setEnd(child_1, 0);
+  selection.addRange(range);
+
+  let state = 0;
+  const states = [2, 4, 3, 5, 1];
+  for (let i = 0; i < 10; ++i) {
+    const id = states[state];
+    selection.extend(document.getElementById(`child_${id}`), 1);
+
+    for (let check_id = 1; check_id <= 5; ++check_id) {
+      if (check_id <= id) {
+        assert_false(
+          isLocked(document.getElementById(`container_${check_id}`)),
+          `test_${i}, container_${check_id}`);
+      } else {
+        assert_true(
+          isLocked(document.getElementById(`container_${check_id}`)),
+          `test_${i}, container_${check_id}`);
+      }
+    }
+    state = (state + 1) % states.length;
+  }
+}, "Range goes back and forth: ");
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-072.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-072.html
new file mode 100644
index 00000000000..9fc8b11ceb2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-072.html
@@ -0,0 +1,86 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: nested forced layouts</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="nested content-visibility items are all processed when layout is forced">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body, html {
+  padding: 0;
+  margin: 0;
+}
+.spacer {
+  height: 3000px;
+}
+.target {
+  width: 12px;
+  height: 34px;
+
+  position: relative;
+  left: 5px;
+  top: 7px;
+}
+
+.auto {
+  content-visibility: auto;
+}
+.hidden {
+  content-visibility: hidden;
+}
+</style>
+
+<div class=spacer></div>
+<div class=auto>
+  <div class=auto>
+    <div class=target id=one></div>
+  </div>
+</div>
+
+<div class=auto>
+  <div class=hidden>
+    <div class=target id=two></div>
+  </div>
+</div>
+
+<div class=hidden>
+  <div class=auto>
+    <div class=target id=three></div>
+  </div>
+</div>
+
+<div class=hidden>
+  <div class=hidden>
+    <div class=target id=four></div>
+  </div>
+</div>
+
+<div class=hidden>
+  <div class=hidden>
+    <div class=hidden>
+      <div class=hidden>
+        <div class=hidden>
+          <div class=target id=five></div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+
+<script>
+const ids = ["one", "two", "three", "four", "five"];
+for (let i = 0; i < ids.length; ++i) {
+  test(() => {
+    const r = document.getElementById(ids[i]).getBoundingClientRect();
+    assert_equals(r.x, 5, "x");
+    assert_equals(r.y, 3007, "y");
+    assert_equals(r.width, 12, "width");
+    assert_equals(r.height, 34, "y");
+  }, `${ids[i]}.getBoundingClientRect(): `);
+}
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-073.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-073.html
new file mode 100644
index 00000000000..62d112c2f72
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/content-visibility-073.html
@@ -0,0 +1,43 @@
+<!doctype HTML>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS Content Visibility: switching to inline starts painting</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<link rel="match" href="inline-container-with-child-ref.html">
+<meta name="assert" content="content-visibility has no effect on non-atomic inlines">
+
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#container {
+  content-visibility: hidden;
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.inline {
+  display: inline;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
+<script>
+function runTest() {
+  const container = document.getElementById("container");
+  container.classList.add("inline");
+  takeScreenshot();
+}
+
+window.onload = () => requestAnimationFrame(runTest);
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inheritance.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inheritance.html
new file mode 100644
index 00000000000..e1ae8164de0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inheritance.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Content Visibility: content-visibility inheritance</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility does not inherit">
+<meta name="assert" content="content-visibility has initial value 'visible'">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+<script src="/css/support/inheritance-testcommon.js"></script>
+</head>
+<body>
+<div id="container">
+<div id="target"></div>
+</div>
+<script>
+assert_not_inherited("content-visibility", "visible", "auto");
+</script>
+</body>
+</html>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inline-container-with-child-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inline-container-with-child-ref.html
new file mode 100644
index 00000000000..af51cbd5db8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/inline-container-with-child-ref.html
@@ -0,0 +1,26 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: container with child and text (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+  display: inline;
+}
+#child {
+  width: 50px;
+  height: 50px;
+  background: lightgreen;
+}
+</style>
+
+<div id=container>
+  Text.
+  <div id=child></div>
+</div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-computed.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-computed.html
new file mode 100644
index 00000000000..6e08deebea0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-computed.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Content Visibility: content-visibility with computed values</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility supports the full grammar 'visible | auto | hidden'.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/computed-testcommon.js"></script>
+</head>
+<body>
+<div id=target></div>
+<div id=scratch></div>
+<script>
+
+test_computed_value("content-visibility", "visible");
+test_computed_value("content-visibility", "auto");
+test_computed_value("content-visibility", "hidden");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-invalid.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-invalid.html
new file mode 100644
index 00000000000..610e219e1ba
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-invalid.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Content Visibility: content-visibility with invalid values</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility supports the full grammar 'visible | auto | hidden'.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_invalid_value("content-visibility", "visible auto");
+test_invalid_value("content-visibility", "foo-bar");
+test_invalid_value("content-visibility", "foo bar baz");
+test_invalid_value("content-visibility", "hidden visible");
+test_invalid_value("content-visibility", "invisible invisible invisible");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-valid.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-valid.html
new file mode 100644
index 00000000000..a0525695ded
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/parsing/content-visibility-valid.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Content Visibility Test: content-visibility with valid values</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+<meta name="assert" content="content-visibility supports the full grammar 'visible | auto | hidden'.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_valid_value("content-visibility", "visible");
+test_valid_value("content-visibility", "auto");
+test_valid_value("content-visibility", "hidden");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/positioned-container-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/positioned-container-ref.html
new file mode 100644
index 00000000000..2ea2c18b0de
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/positioned-container-ref.html
@@ -0,0 +1,22 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>CSS Content Visibility: positioned container (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightblue;
+}
+.positioned {
+  position: absolute;
+  top: 0;
+  left: 0;
+}
+</style>
+
+<div id=container class=positioned></div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/circles.svg b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/circles.svg
new file mode 100644
index 00000000000..1a9ad7534da
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/circles.svg
@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="iso-8859-1" ?>
+<svg viewBox="0 0 500 300" xmlns="http://www.w3.org/2000/svg">
+<rect x="0" y="0" width="500" height="300" fill="#fff" />
+
+<g stroke-width="10" transform="translate(-30)">
+    <circle cx="80" cy="50" r="35" fill="#084" stroke="none"/>
+    <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="120" r="35" fill="#004" stroke="none"/>
+    <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="190" r="35" fill="#088" stroke="none"/>
+    <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="260" r="35" fill="#008" stroke="none"/>
+    <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+</g>
+
+<g stroke-width="10" transform="translate(170)">
+    <circle cx="80" cy="50" r="35" fill="#085" stroke="none"/>
+    <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="120" r="35" fill="#005" stroke="none"/>
+    <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="190" r="35" fill="#689" stroke="none"/>
+    <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="260" r="35" fill="#609" stroke="none"/>
+    <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+</g>
+
+<g stroke-width="10" transform="translate(370)">
+    <circle cx="80" cy="50" r="35" fill="#084" stroke="none"/>
+    <circle cx="80" cy="50" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="120" r="35" fill="#084" stroke="none"/>
+    <circle cx="80" cy="120" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="190" r="35" fill="#088" stroke="none"/>
+    <circle cx="80" cy="190" r="20" fill="#080" stroke="#FF0"/>
+    <circle cx="80" cy="260" r="35" fill="#088" stroke="none"/>
+    <circle cx="80" cy="260" r="20" fill="#080" stroke="#FF0"/>
+</g>
+</svg>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/dice.png b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/dice.png
new file mode 100644
index 00000000000..f18b8141764
Binary files /dev/null and b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/dice.png differ
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/frame.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/frame.html
new file mode 100644
index 00000000000..14f48b99a8b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/frame.html
@@ -0,0 +1,8 @@
+<!doctype HTML>
+<style>
+div {
+  background: lightgreen;
+}
+</style>
+<div>dolor sit amet</div>
+
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/text-fragment-target-auto.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/text-fragment-target-auto.html
new file mode 100644
index 00000000000..d07ede5a546
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/resources/text-fragment-target-auto.html
@@ -0,0 +1,64 @@
+<!doctype html>
+<title>Text fragment navigation helper.</title>
+
+<script src="/scroll-to-text-fragment/stash.js"></script>
+<script>
+function isInView(element) {
+  let rect = element.getBoundingClientRect();
+  return rect.top >= 0 && rect.top <= window.innerHeight
+      && rect.left >= 0 && rect.left <= window.innerWidth;
+}
+function checkScroll() {
+  let position = 'unknown';
+  if (window.scrollY == 0)
+    position = 'top';
+  else if(isInView(document.getElementById("text")))
+    position = 'text';
+  else if(isInView(document.getElementById("text2")))
+    position = 'text2';
+  else if(isInView(document.getElementById("text3")))
+    position = 'text3';
+
+  const target = document.querySelector(":target");
+  let results = {
+    scrollPosition: position,
+    href: window.location.href,
+    target: target ? target.id : 'undefined'
+  };
+  let key = (new URL(document.location)).searchParams.get("key");
+  stashResultsThenClose(key, results);
+}
+function doubleRafCheckScroll() {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      checkScroll();
+    });
+  });
+}
+</script>
+
+<style>
+.spacer {
+  height: 10000px;
+}
+.auto {
+  subtree-visibility: auto;
+}
+</style>
+
+<body onload="doubleRafCheckScroll()">
+<div class=spacer></div>
+<div class=auto>
+  <div id=text>hiddentext</div>
+</div>
+<div class=spacer></div>
+<div id=text2and3ancestor>
+  <div class=auto>
+    <div id=text2>start</div>
+  </div>
+  <div class=spacer></div>
+  <div class=auto>
+    <div id=text3>end</div>
+  </div>
+</div>
+</body>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-ref.html
new file mode 100644
index 00000000000..c605d2ab9c2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-ref.html
@@ -0,0 +1,23 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: spacer and a container (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  contain: style layout;
+  width: 150px;
+  height: 150px;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"></div>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-scrolled-ref.html b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-scrolled-ref.html
new file mode 100644
index 00000000000..ed189c7d306
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-contain/content-visibility/spacer-and-container-scrolled-ref.html
@@ -0,0 +1,27 @@
+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Content Visibility: spacer and a container, scrolled to container (reference)</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
+
+<style>
+.spacer {
+  width: 150px;
+  height: 3000px;
+  background: lightblue;
+}
+#container {
+  width: 150px;
+  height: 150px;
+  background: lightgreen;
+}
+</style>
+
+<div class="spacer"></div>
+<div id="container"></div>
+
+<script>
+onload = () => container.scrollIntoView();
+</script>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-multicol/as-column-flex-item.html b/tests/wpt/web-platform-tests/css/css-multicol/as-column-flex-item.html
new file mode 100644
index 00000000000..21ff8d8d50c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-multicol/as-column-flex-item.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://www.w3.org/TR/css-multicol-1/">
+<link rel="help" href="https://www.w3.org/TR/css-sizing-3/">
+<meta name="assert" content="Tests that the intrinsic block-size of a multicol container is calculated correctly, including the border">
+<link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div style="width:100px; height:100px; background:red;">
+  <div style="display:flex; flex-flow:column; background:red;">
+    <div style="columns:4; column-gap:0; border:30px solid green; width:40px;">
+      <div style="height:160px; background:green;"></div>
+    </div>
+  </div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-scroll-anchoring/contain-paint-offscreen-container.html b/tests/wpt/web-platform-tests/css/css-scroll-anchoring/contain-paint-offscreen-container.html
new file mode 100644
index 00000000000..58f41cc7480
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-scroll-anchoring/contain-paint-offscreen-container.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<meta charset="utf8">
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-scroll-anchoring/">
+<meta name="assert" content="ensures that scroll anchoring does not recurse into contained offscreen elements">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body { height: 10000px; }
+#container { contain: paint; }
+#overflow {
+  position: relative;
+  top: 300px;
+  height: 10px;
+}
+#anchor {
+  width: 10px;
+  height: 50px;
+}
+</style>
+
+<div style="height: 800px"></div>
+<div id="container" style="height: 40px">
+  <div id=overflow></div>
+</div>
+<div id="changer" style="height: 150px"></div>
+<div id=anchor></div>
+
+<script>
+test(() => {
+  // Ensure #anchor is the only thing on screen.
+  // Note that #overflow would be on screen if container
+  // did not have layout and paint containment.
+  document.scrollingElement.scrollTop = 1000;
+
+  // Ensure anchor doesn't move if #changer shrinks.
+  const offset = anchor.getBoundingClientRect().y;
+  document.querySelector("#changer").style.height = "50px";
+  assert_equals(anchor.getBoundingClientRect().y, offset);
+}, "Contain: style paint container offscreen.");
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006-ref.html b/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006-ref.html
new file mode 100644
index 00000000000..a9584d2329f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006-ref.html
@@ -0,0 +1,5 @@
+<!DOCTYPE html>
+<title>backface visibility: hidden scrolling contents if backface-invisible</title>
+<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
+<link rel="help" href="http://www.w3.org/TR/css-transforms-1/#transform-property">
+<link rel="help" href="http://www.w3.org/TR/css-transforms-2/#propdef-backface-visibility">
diff --git a/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006.html b/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006.html
new file mode 100644
index 00000000000..096145efec1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-transforms/backface-visibility-hidden-006.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<title>backface visibility: hidden scrolling contents if backface-invisible</title>
+<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
+<link rel="help" href="http://www.w3.org/TR/css-transforms-1/#transform-property">
+<link rel="help" href="http://www.w3.org/TR/css-transforms-2/#propdef-backface-visibility">
+<link rel="match" href="backface-visibility-hidden-006-ref.html">
+<div style="transform: rotateY(180deg); backface-visibility: hidden; overflow: scroll; height: 300px;">
+  <p style="display: inline-block; height: 300px">
+    This text should be invisible
+  </p>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/mediaqueries/prefers-reduced-data.html b/tests/wpt/web-platform-tests/css/mediaqueries/prefers-reduced-data.html
index 003dad4c8b6..4c2668fe78e 100644
--- a/tests/wpt/web-platform-tests/css/mediaqueries/prefers-reduced-data.html
+++ b/tests/wpt/web-platform-tests/css/mediaqueries/prefers-reduced-data.html
@@ -28,11 +28,14 @@ query_should_not_be_js_parseable("(prefers-reduced-data: reduced)");
 query_should_not_be_js_parseable("(prefers-reduced-data: no-preference/reduce)");
 
 test(() => {
-  // What this is saying is that 'no-preference' is not the default, so
-  // irregardless of the current OS settings, (prefers-reduced-data).matches
-  // should not be equivalent to (prefers-reduced-data: no-preference).matches.
+  // https://drafts.csswg.org/mediaqueries-5/#boolean-context
   let booleanContext = window.matchMedia("(prefers-reduced-data)");
   let noPreference = window.matchMedia("(prefers-reduced-data: no-preference)");
   assert_equals(booleanContext.matches, !noPreference.matches);
 }, "Check that no-preference evaluates to false in the boolean context");
+
+test(() => {
+  let invalid = window.matchMedia("(prefers-reduced-data: 10px)");
+  assert_equals(invalid.matches, false);
+}, "Check that invalid evaluates to false");
 </script>
diff --git a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/resources/reporting-common.js b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/resources/reporting-common.js
index d834c080e44..0b96a0f6c81 100644
--- a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/resources/reporting-common.js
+++ b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/resources/reporting-common.js
@@ -7,6 +7,19 @@ function wait(ms) {
   return new Promise(resolve => step_timeout(resolve, ms));
 }
 
+// Check whether a |report| is a "opener breakage" COOP report.
+function isCoopOpenerBreakageReport(report) {
+  if (report.type != "coop")
+    return false;
+
+  if (report.body["violation-type"] != "navigation-from-document" &&
+      report.body["violation-type"] != "navigation-to-document") {
+    return false;
+  }
+
+  return true;
+}
+
 async function pollReports(endpoint) {
   const res = await fetch(
       `resources/report.py?endpoint=${endpoint.name}`,
@@ -15,7 +28,8 @@ async function pollReports(endpoint) {
     return;
   }
   for (const report of await res.json()) {
-    endpoint.reports.push(report);
+    if (isCoopOpenerBreakageReport(report))
+      endpoint.reports.push(report);
   }
 }
 
diff --git a/tests/wpt/web-platform-tests/interfaces/native-file-system.idl b/tests/wpt/web-platform-tests/interfaces/native-file-system.idl
index 60a28f055de..92d05fe4659 100644
--- a/tests/wpt/web-platform-tests/interfaces/native-file-system.idl
+++ b/tests/wpt/web-platform-tests/interfaces/native-file-system.idl
@@ -75,25 +75,31 @@ interface FileSystemWritableFileStream : WritableStream {
   Promise<void> truncate(unsigned long long size);
 };
 
-enum ChooseFileSystemEntriesType { "open-file", "save-file", "open-directory" };
-
-dictionary ChooseFileSystemEntriesOptionsAccepts {
-  USVString description;
-  sequence<USVString> mimeTypes;
-  sequence<USVString> extensions;
+dictionary FilePickerAcceptType {
+    USVString description;
+    record<USVString, sequence<USVString>> accept;
 };
 
-dictionary ChooseFileSystemEntriesOptions {
-    ChooseFileSystemEntriesType type = "open-file";
-    boolean multiple = false;
-    sequence<ChooseFileSystemEntriesOptionsAccepts> accepts;
+dictionary FilePickerOptions {
+    sequence<FilePickerAcceptType> types;
     boolean excludeAcceptAllOption = false;
 };
 
+dictionary OpenFilePickerOptions : FilePickerOptions {
+    boolean multiple = false;
+};
+
+dictionary SaveFilePickerOptions : FilePickerOptions {
+};
+
+dictionary DirectoryPickerOptions {
+};
+
 [SecureContext]
 partial interface Window {
-    Promise<(FileSystemHandle or sequence<FileSystemHandle>)>
-        chooseFileSystemEntries(optional ChooseFileSystemEntriesOptions options = {});
+    Promise<sequence<FileSystemFileHandle>> showOpenFilePicker(optional OpenFilePickerOptions options = {});
+    Promise<FileSystemFileHandle> showSaveFilePicker(optional SaveFilePickerOptions options = {});
+    Promise<FileSystemDirectoryHandle> showDirectoryPicker(optional DirectoryPickerOptions options = {});
 };
 
 [SecureContext]
diff --git a/tests/wpt/web-platform-tests/lint.ignore b/tests/wpt/web-platform-tests/lint.ignore
index db7f36426b1..c6ec444f6cc 100644
--- a/tests/wpt/web-platform-tests/lint.ignore
+++ b/tests/wpt/web-platform-tests/lint.ignore
@@ -615,6 +615,8 @@ CSS-COLLIDING-SUPPORT-NAME: css/css-display/support/util.js
 CSS-COLLIDING-SUPPORT-NAME: css/CSS2/normal-flow/support/replaced-min-max-1.png
 CSS-COLLIDING-SUPPORT-NAME: css/vendor-imports/mozilla/mozilla-central-reftests/ui3/support/replaced-min-max-1.png
 
+CSS-COLLIDING-TEST-NAME: css/css-contain/inheritance.html
+CSS-COLLIDING-TEST-NAME: css/css-contain/content-visibility/inheritance.html
 CSS-COLLIDING-TEST-NAME: css/css-sizing/contain-intrinsic-size/parsing/contain-intrinsic-size-invalid.html
 CSS-COLLIDING-TEST-NAME: css/css-sizing/aspect-ratio/parsing/contain-intrinsic-size-invalid.html
 CSS-COLLIDING-TEST-NAME: css/css-sizing/contain-intrinsic-size/parsing/contain-intrinsic-size-computed.html
diff --git a/tests/wpt/web-platform-tests/mathml/relations/html5-tree/dynamic-childlist-002.html b/tests/wpt/web-platform-tests/mathml/relations/html5-tree/dynamic-childlist-002.html
new file mode 100644
index 00000000000..d874e80bbba
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/relations/html5-tree/dynamic-childlist-002.html
@@ -0,0 +1,102 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Dynamic childlist of MathML elements</title>
+<script src="/mathml/support/mathml-fragments.js"></script>
+<link rel="help" href="https://mathml-refresh.github.io/mathml-core/#adjust-space-around-content-mpadded">
+<link rel="help" href="https://mathml-refresh.github.io/mathml-core/#dom-and-javascript">
+<meta name="assert" content="Dynamically modify DOM tree of some MathML elements by adding or removing children.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/mathml/support/feature-detection.js"></script>
+<script src="/mathml/support/layout-comparison.js"></script>
+<script>
+  function generateMathForTag(tag, childCount) {
+      let math = FragmentHelper.createElement("math");
+      let element = FragmentHelper.createElement(tag);
+      // Add the children with sizes of different sizes at odd positions and OOF
+      // mrow at even position.
+      for (let i = 0; i < childCount; i++) {
+          if (i % 2) {
+              let mspace = FragmentHelper.createElement("mspace");
+              mspace.setAttribute("width", `10px`);
+              mspace.setAttribute("height", `${10*(i+1)}px`);
+              mspace.setAttribute("style", `background: black;`);
+              element.appendChild(mspace);
+          } else {
+              let mrow = FragmentHelper.createElement("mrow");
+              mrow.setAttribute("style", "position: absolute");
+              element.appendChild(mrow);
+          }
+      }
+      math.appendChild(element);
+      return math;
+  }
+
+  setup({ explicit_done: true });
+  window.addEventListener("load", function() {
+
+      for (tag in MathMLFragments) {
+          if (!FragmentHelper.isValidChildOfMrow(tag))
+              continue;
+
+          document.body.insertAdjacentHTML("beforeend", `<div style='display: none; background: pink;'>${tag}: <div></div><div></div><div></div></div>`);
+
+          let container = document.body.lastElementChild;
+          let referenceDiv = container.children[0];
+          const maxChild = 10;
+          const epsilon = 1;
+
+          // Create the references for different number of children as well
+          // as the element that will get the children added / removed.
+          for (let i = 0; i <= maxChild; i++)
+              referenceDiv.append(generateMathForTag(tag, i));
+          let fullReferenceMath = referenceDiv.lastElementChild;
+          let fullReferenceTag = fullReferenceMath.firstElementChild;
+
+          let removeChildrenMath = generateMathForTag(tag, maxChild);
+          container.children[1].append(removeChildrenMath);
+          let removeChildrenTag = removeChildrenMath.firstElementChild;
+
+          let appendChildrenMath = generateMathForTag(tag, 0);
+          container.children[2].append(appendChildrenMath);
+          let appendChildrenTag = appendChildrenMath.firstElementChild;
+
+          // Make content visible after the DOM is ready so that the layout
+          // only happens now.
+          container.style.display = "block";
+
+          test(function() {
+              assert_true(MathMLFeatureDetection.has_mspace());
+              assert_true(MathMLFeatureDetection[`has_${tag}`]());
+
+              for (let i = 0; i < maxChild; i++) {
+                  // append and remove children.
+                  appendChildrenTag.append(fullReferenceTag.children[i].cloneNode(true));
+                  removeChildrenTag.removeChild(removeChildrenTag.lastElementChild);
+
+                  // force layout so we're sure what we're testing against
+                  container.getBoundingClientRect();
+
+                  let appendCount = appendChildrenTag.children.length;
+                  compareLayout(appendChildrenTag, referenceDiv.children[appendCount].firstElementChild, epsilon, `appending ${appendCount}-th child`);
+
+                  let removeCount = removeChildrenTag.children.length;
+                  compareLayout(removeChildrenTag, referenceDiv.children[removeCount].firstElementChild, epsilon, `removing ${appendCount + 1}-th child`);
+              }
+
+              // Hide back the div after successful testing.
+              container.style.display = "none";
+
+          }, `Appending and removing children to ${tag}`);
+      }
+
+      done();
+  });
+</script>
+</head>
+<body>
+  <div id="log"></div>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/native-io/close_async.tentative.https.any.js b/tests/wpt/web-platform-tests/native-io/close_async.tentative.https.any.js
index a992f93eb53..6ad27ffb447 100644
--- a/tests/wpt/web-platform-tests/native-io/close_async.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/native-io/close_async.tentative.https.any.js
@@ -10,7 +10,7 @@ async function createFile(testCase, fileName) {
   const file = await nativeIO.open(fileName);
   testCase.add_cleanup(async () => {
     await file.close();
-    await nativeIO.delete('test_file');
+    await nativeIO.delete(fileName);
   });
 
   const writeSharedArrayBuffer = new SharedArrayBuffer(4);
diff --git a/tests/wpt/web-platform-tests/native-io/close_sync.tentative.https.any.js b/tests/wpt/web-platform-tests/native-io/close_sync.tentative.https.any.js
index 8897d66f2cc..e4f5871a65e 100644
--- a/tests/wpt/web-platform-tests/native-io/close_sync.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/native-io/close_sync.tentative.https.any.js
@@ -10,7 +10,7 @@ function createFileSync(testCase, fileName) {
   const file = nativeIO.openSync(fileName);
   testCase.add_cleanup(() => {
     file.close();
-    nativeIO.deleteSync('test_file');
+    nativeIO.deleteSync(fileName);
   });
 
   const writtenBytes = Uint8Array.from([64, 65, 66, 67]);
diff --git a/tests/wpt/web-platform-tests/native-io/concurrent_io_async.tentative.https.any.js b/tests/wpt/web-platform-tests/native-io/concurrent_io_async.tentative.https.any.js
index abc2031d5f9..d7752004678 100644
--- a/tests/wpt/web-platform-tests/native-io/concurrent_io_async.tentative.https.any.js
+++ b/tests/wpt/web-platform-tests/native-io/concurrent_io_async.tentative.https.any.js
@@ -10,7 +10,7 @@ async function createFile(testCase, fileName) {
   const file = await nativeIO.open(fileName);
   testCase.add_cleanup(async () => {
     await file.close();
-    await nativeIO.delete('test_file');
+    await nativeIO.delete(fileName);
   });
 
   const writeSharedArrayBuffer = new SharedArrayBuffer(4);
diff --git a/tests/wpt/web-platform-tests/origin-isolation/going-back.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/going-back.sub.https.html
index 781e3640d3b..7e95f193669 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/going-back.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/going-back.sub.https.html
@@ -7,33 +7,24 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, navigateIframe, waitForIframe, sendWasmModule,
-         setBothDocumentDomains, sendWasmModuleBetween, accessDocumentBetween }
-       from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  navigateIframe,
+  waitForIframe,
+  setBothDocumentDomains,
+  testDifferentAgentClusters,
+  testSameAgentCluster,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frame1, frameWindow2;
+let frame1;
 promise_setup(async () => {
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frame1 = document.querySelector("iframe");
+  frame1 = await insertIframe("{{hosts[][www]}}");
 });
 
 // Since they're different-origin, the parent's isolation request is respected,
 // as is the child's non-request. So the parent ends up in the origin-keyed
 // agent cluster and the child ends up in the site-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Before navigation: parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow1);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Before navigation: parent to child1: setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0], "Before navigation: parent to child1");
 
 // Navigate the iframe to a different site. These, of course, must not be in the
 // same agent cluster.
@@ -48,22 +39,10 @@ promise_test(async () => {
 // iframe should still end up in the site-keyed agent cluster.
 
 promise_test(async () => {
-  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}", "?1");
 }, "Inserting a second iframe");
 
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "After navigation: parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow2);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "After navigation: parent to child2: setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 1], "After navigation: parent to child2");
 
 // Now navigate the first iframe back. The resulting Document should be put in
 // the site agent cluster, together with the second iframe's Document.
@@ -73,58 +52,11 @@ promise_test(async () => {
   history.back();
   await waitPromise;
 
-  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frames[0]);
 }, "Going back in history (navigating back the first iframe)");
 
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "After back: parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow2);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "After back: parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "After back: parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow1);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "After back: parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "After back: parent to child1");
+testDifferentAgentClusters([self, 1], "After back: parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/insecure-http.sub.html b/tests/wpt/web-platform-tests/origin-isolation/insecure-http.sub.html
index 04d4b2b6365..1e78b133857 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/insecure-http.sub.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/insecure-http.sub.html
@@ -7,26 +7,13 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 // All isolation requests are ignored, since this is over insecure HTTP.
 // So both end up in the site-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "message event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  // Must not throw
-  frameWindow.document;
-}, "setting document.domain must give sync access");
+testSameAgentCluster([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-bad-subdomain.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-bad-subdomain.sub.https.html
index 2653dabd980..ae55f5d83e1 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-bad-subdomain.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-bad-subdomain.sub.https.html
@@ -7,27 +7,16 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
+let frameIndex = 0;
 for (const badValue of ["", "?0", "true", "\"?1\"", "1", "?2", "(?1)"]) {
-  let frameWindow;
   promise_test(async () => {
-    frameWindow = await insertIframe("{{hosts[][www]}}", badValue);
+    await insertIframe("{{hosts[][www]}}", badValue);
   }, `"${badValue}": frame insertion`);
 
   // Since the header values are bad there should be no isolation
-
-  promise_test(async () => {
-    const whatHappened = await sendWasmModule(frameWindow);
-
-    assert_equals(whatHappened, "WebAssembly.Module message received");
-  }, `"${badValue}": message event must occur for`);
-
-  promise_test(async () => {
-    await setBothDocumentDomains(frameWindow);
-
-    // Must not throw
-    frameWindow.document;
-  }, `"${badValue}": setting document.domain must give sync access`);
+  testSameAgentCluster([self, frameIndex], `"${badValue}"`);
+  ++frameIndex;
 }
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-same.sub.https.html
index 4239e164463..8e32649d3a2 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-same.sub.https.html
@@ -7,26 +7,13 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][]}}", "?1");
+  await insertIframe("{{hosts[][]}}", "?1");
 });
 
 // Since they're same-origin, and the parent loaded without isolation, the
 // child's request for isolation gets ignored, and both end up site-keyed.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "message event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  // Must not throw
-  frameWindow.document;
-}, "setting document.domain must give sync access");
+testSameAgentCluster([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-subdomain.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-subdomain.sub.https.html
index f2389eaa6a0..7f4a9413e35 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-subdomain.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-subdomain.sub.https.html
@@ -7,28 +7,14 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testDifferentAgentClusters } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 // Since they're different-origin, the child's isolation request is respected,
 // so the parent ends up in the site-keyed agent cluster and the child in the
 // origin-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "messageerror");
-}, "messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow.document;
-  });
-}, "setting document.domain should no-op instead of giving sync access");
+testDifferentAgentClusters([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-with-params-subdomain.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-with-params-subdomain.sub.https.html
index 164a19ff381..0208ac3e14c 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-with-params-subdomain.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child-yes-with-params-subdomain.sub.https.html
@@ -7,28 +7,14 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testDifferentAgentClusters } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][www]}}", "?1;param1;param2=value2");
+  await insertIframe("{{hosts[][www]}}", "?1;param1;param2=value2");
 });
 
 // Since they're different-origin, the child's isolation request is respected,
 // so the parent ends up in the site-keyed agent cluster and the child in the
 // origin-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "messageerror");
-}, "messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow.document;
-  });
-}, "setting document.domain should no-op instead of giving sync access");
+testDifferentAgentClusters([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html
index 3c879391a45..c019ef2fe7d 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html
@@ -7,18 +7,17 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
   // Order of loading should not matter, but we make it sequential to ensure the
   // tests are deterministic.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www1]}}", "?1");
 });
 
 
@@ -27,51 +26,8 @@ promise_setup(async () => {
 //
 // So, the parent and child 1 end up in the site-keyed agent cluster, and child
 // 2 ends up in its own origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "Parent to child1: message event must occur");
-
-promise_test(async () => {
-  // Must not throw
-  frameWindow1.document;
-}, "Parent to child1: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child1 to child2: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child1 to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child2 to child1: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child2 to child1: setting document.domain must not give sync access");
+testSameAgentCluster([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testDifferentAgentClusters([0, 1], "child1 to child2");
+testDifferentAgentClusters([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html
index 5d9161a852f..9ca18f8941b 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html
@@ -7,69 +7,22 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
-  // Must be sequential, not parallel: frameWindow1 must load first.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  // Must be sequential, not parallel: the non-isolated frame must load first.
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 
 // Since they're different-origin, the parent's isolation non-request is
-// respected, as is frameWindow1's non-request. frameWindow2 requests isolation
-// but is ignored, since frameWindow1 is in the same browsing context group.
+// respected, as is child 1's non-request. child 2 requests isolation
+// but is ignored, since child 1 is in the same browsing context group.
 //
 // So, everyone ends up in the site-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "Parent to child1: message event must occur");
-
-promise_test(async () => {
-  // Must not throw
-  frameWindow1.document;
-}, "Parent to child1: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "Parent to child2: message event must occur");
-
-promise_test(async () => {
-  // Must not throw
-  frameWindow2.document;
-}, "Parent to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testSameAgentCluster([self, 0], "Parent to child1");
+testSameAgentCluster([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html
index d289c8821ae..2947e629bd5 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html
@@ -7,72 +7,27 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
-  // Must be sequential, not parallel: frameWindow1 must load first.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  // Must be sequential, not parallel: the isolated frame must load first.
+  await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}");
 });
 
 
 // Since they're different-origin, the parent's isolation non-request is
-// respected, as is frameWindow1's request. frameWindow2's non-request is
-// ignored, since frameWindow1 is in the same browsing context group.
+// respected, as is child 1's request. child 2's non-request is
+// ignored, since child 1 is in the same browsing context group.
 //
 // So, the parent ends up in the site-keyed agent cluster, and both children end
 // up in an origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-same.sub.https.html
index a1b9e4e3f5a..aa1dd94682e 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-same.sub.https.html
@@ -7,26 +7,13 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][]}}");
+  await insertIframe("{{hosts[][]}}");
 });
 
 // Since they're same-origin, and the parent loaded with isolation, the
 // child's non-request for isolation gets ignored, and both end up origin-keyed.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "message event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  // Must not throw
-  frameWindow.document;
-}, "setting document.domain must give sync access");
+testSameAgentCluster([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-subdomain.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-subdomain.sub.https.html
index b167b1b4954..5055d295d03 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-subdomain.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-no-subdomain.sub.https.html
@@ -7,28 +7,14 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testDifferentAgentClusters } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www]}}");
 });
 
 // Since they're different-origin, the parent's isolation request is respected,
 // as is the child's non-request. So the parent ends up in the origin-keyed
 // agent cluster and the child ends up in the site-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "messageerror");
-}, "messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow.document;
-  });
-}, "setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-same.sub.https.html
index f43526cd552..3d99486a3cb 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-same.sub.https.html
@@ -7,26 +7,13 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testSameAgentCluster } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][]}}", "?1");
+  await insertIframe("{{hosts[][]}}", "?1");
 });
 
 // Both request isolation, and they're same-origin, so they both end up in the
 // same origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "message event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  // Must not throw
-  frameWindow.document;
-}, "setting document.domain must give sync access");
+testSameAgentCluster([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-subdomain.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-subdomain.sub.https.html
index 5c3567cee57..afc8f5b2acd 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-subdomain.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child-yes-subdomain.sub.https.html
@@ -7,28 +7,14 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains } from "./resources/helpers.mjs";
+import { insertIframe, testDifferentAgentClusters } from "./resources/helpers.mjs";
 
-let frameWindow;
 promise_setup(async () => {
-  frameWindow = await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 // Both request isolation, so the parent ends up in one origin-keyed agent
 // cluster (the base domain's origin), and the child ends up in a different
 // origin-keyed agent cluster (the www subdomain's origin).
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow);
-
-  assert_equals(whatHappened, "messageerror");
-}, "messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow.document;
-  });
-}, "setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0]);
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-different.sub.https.html
index ad1e58a16c1..77a77d50a1c 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-different.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-different.sub.https.html
@@ -7,18 +7,17 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
   // Order of loading should not matter, but we make it sequential to ensure the
   // tests are deterministic.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www1]}}");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www1]}}");
 });
 
 
@@ -27,52 +26,8 @@ promise_setup(async () => {
 //
 // So, the parent ends up in its origin-keyed agent cluster, and child 1 and
 // child 2 both end up in the site-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-same.sub.https.html
index ceed3a562f0..b3f18e8560f 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-no-children-same.sub.https.html
@@ -7,18 +7,17 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
   // Order of loading should not matter, but we make it sequential to ensure the
   // tests are deterministic.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www]}}");
 });
 
 
@@ -27,52 +26,8 @@ promise_setup(async () => {
 //
 // So, the parent ends up in its origin-keyed agent cluster, and child 1 and
 // child 2 both end up in the site-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html
index 6b09b36a586..8e7b4d3ee5c 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html
@@ -7,18 +7,17 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
   // Order of loading should not matter, but we make it sequential to ensure the
   // tests are deterministic.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www1]}}", "?1");
 });
 
 
@@ -28,52 +27,8 @@ promise_setup(async () => {
 // So, the parent ends up in its origin-keyed agent cluster, child 1 ends up in
 // the site-keyed agent cluster, and child 2 ends up in a different origin-keyed
 // agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child1 to child2: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child1 to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child2 to child1: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child2 to child1: setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testDifferentAgentClusters([0, 1], "child1 to child2");
+testDifferentAgentClusters([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html
index b3616a604b9..260ac80d2ff 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html
@@ -7,72 +7,27 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
-  // Must be sequential, not parallel: frameWindow1 must load first.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  // Must be sequential, not parallel: the non-isolaed frame must load first.
+  await insertIframe("{{hosts[][www]}}");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 
 // Since they're different-origin, the parent's isolation request is respected,
-// as is frameWindow1's non-request. frameWindow2 requests isolation but is
-// ignored, since frameWindow1 is in the same browsing context group.
+// as is child 1's non-request. child 2 requests isolation but is
+// ignored, since child 1 is in the same browsing context group.
 //
 // So, the parent ends up in the origin-keyed agent cluster, and both children
 // ends up in the site-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html
index 7e351aaf14a..ae54fcd02ea 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html
@@ -7,72 +7,27 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
-  // Must be sequential, not parallel: frameWindow1 must load first.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  // Must be sequential, not parallel: the isolated frame must load first.
+  await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}");
 });
 
 
 // Since they're different-origin, the parent's isolation request is respected,
-// as is frameWindow1's request. frameWindow2's non-request is ignored, since
-// frameWindow1 is in the same browsing context group.
+// as is child 1's request. child 2's non-request is ignored, since
+// child 1 is in the same browsing context group.
 //
 // So, the parent ends up in the origin-keyed agent cluster, and both children
 // ends up in a different origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html
index f7c7ea81459..775f753561b 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html
@@ -7,18 +7,17 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
   // Order of loading should not matter, but we make it sequential to ensure the
   // tests are deterministic.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
-  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www1]}}", "?1");
 });
 
 
@@ -28,52 +27,8 @@ promise_setup(async () => {
 // So, the parent ends up in its origin-keyed agent cluster, child 1 ends up in
 // a second origin-keyed agent cluster, and child 2 ends up in a third
 // origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child1 to child2: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child1 to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "messageerror");
-}, "child2 to child1: messageerror event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "SecurityError");
-}, "child2 to child1: setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testDifferentAgentClusters([0, 1], "child1 to child2");
+testDifferentAgentClusters([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html
index ca5528e5096..a3b0939862c 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html
@@ -7,72 +7,28 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, sendWasmModule, setBothDocumentDomains,
-         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frameWindow1, frameWindow2;
 promise_setup(async () => {
-  // Must be sequential, not parallel: frameWindow1 must load first.
-  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
-  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
-
-  await setBothDocumentDomains(frameWindow1);
-  await setBothDocumentDomains(frameWindow2);
+  // Order of loading should not matter, but we make it sequential to ensure the
+  // tests are deterministic.
+  await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www]}}", "?1");
 });
 
 
 // Since they're different-origin, the parent's isolation request is respected,
-// as is frameWindow1's request. frameWindow2's request is redundant, since
-// frameWindow1 is in the same browsing context group.
+// as is child 1's request. child 2's request is redundant, since
+// child 1 is in the same browsing context group.
 //
 // So, the parent ends up in the origin-keyed agent cluster, and both children
 // ends up in a different origin-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child1: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Parent to child1: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child1 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child1 to child2: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child1: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child1: setting document.domain must give sync access");
+testDifferentAgentClusters([self, 0], "Parent to child1");
+testDifferentAgentClusters([self, 1], "Parent to child2");
+testSameAgentCluster([0, 1], "child1 to child2");
+testSameAgentCluster([1, 0], "child2 to child1");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/removing-iframes.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/removing-iframes.sub.https.html
index 0d2d97815e2..2f01562b04c 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/removing-iframes.sub.https.html
+++ b/tests/wpt/web-platform-tests/origin-isolation/removing-iframes.sub.https.html
@@ -7,93 +7,34 @@
 <div id="log"></div>
 
 <script type="module">
-import { insertIframe, navigateIframe, waitForIframe, sendWasmModule,
-         setBothDocumentDomains, sendWasmModuleBetween, accessDocumentBetween }
-       from "./resources/helpers.mjs";
+import {
+  insertIframe,
+  testSameAgentCluster,
+  testDifferentAgentClusters,
+} from "./resources/helpers.mjs";
 
-let frame1, frameWindow1, frameWindow2, frameWindow3;
+let frame1;
 promise_setup(async () => {
-  frameWindow1 = await insertIframe("{{hosts[][www]}}");
-  frame1 = document.querySelector("iframe");
+  frame1 = await insertIframe("{{hosts[][www]}}");
 });
 
 // Since they're different-origin, the parent's isolation request is respected,
 // as is the child's non-request. So the parent ends up in the origin-keyed
 // agent cluster and the child ends up in the site-keyed one.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow1);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Before: messageerror event must occur");
-
-promise_test(async () => {
-  await setBothDocumentDomains(frameWindow1);
-
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow1.document;
-  });
-}, "Before: setting document.domain must not give sync access");
+testDifferentAgentClusters([self, 0], "Before");
 
 promise_test(async () => {
   frame1.remove();
 
-  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
-  frameWindow3 = await insertIframe("{{hosts[][www1]}}");
-
-  await setBothDocumentDomains(frameWindow2);
-  await setBothDocumentDomains(frameWindow3);
+  await insertIframe("{{hosts[][www]}}", "?1");
+  await insertIframe("{{hosts[][www1]}}");
 }, "Remove the iframe and insert new ones");
 
 // Because of the historical presence of a non-isolated {{hosts[][www]}} iframe,
-// the origin isolation request for frameWindow2 will be ignored. So,
-// frameWindow2 and frameWindow3 both end up in the site-keyed agent cluster.
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow2);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child2: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow2.document;
-  });
-}, "Parent to child2: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModule(frameWindow3);
-
-  assert_equals(whatHappened, "messageerror");
-}, "Parent to child3: messageerror event must occur");
-
-promise_test(async () => {
-  assert_throws_dom("SecurityError", DOMException, () => {
-    frameWindow3.document;
-  });
-}, "Parent to child3: setting document.domain must not give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow2, 1);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child2 to child3: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow2, 1);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child2 to child3: setting document.domain must give sync access");
-
-promise_test(async () => {
-  const whatHappened = await sendWasmModuleBetween(frameWindow3, 0);
-
-  assert_equals(whatHappened, "WebAssembly.Module message received");
-}, "child3 to child2: message event must occur");
-
-promise_test(async () => {
-  const whatHappened = await accessDocumentBetween(frameWindow3, 0);
-
-  assert_equals(whatHappened, "accessed document successfully");
-}, "child3 to child2: setting document.domain must give sync access");
+// the origin isolation request for child 2 will be ignored. So,
+// child 2 and child 3 both end up in the site-keyed agent cluster.
+testDifferentAgentClusters([self, 0], "Parent to child2");
+testDifferentAgentClusters([self, 1], "Parent to child3");
+testSameAgentCluster([0, 1], "child2 to child3");
+testSameAgentCluster([1, 0], "child3 to child2");
 </script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs b/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
index 68478580925..4b742c2b6e7 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
+++ b/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
@@ -1,21 +1,53 @@
-export function insertIframe(hostname, header) {
+/**
+ * Inserts an iframe usable for origin isolation testing, and returns a promise
+ * fulfilled when the iframe is loaded and its document.domain is set. The
+ * iframe will point to the send-origin-isolation-header.py file, on the
+ * designated hostname
+ * @param {string} hostname - The hostname used to calculate the iframe's src=""
+ * @param {string=} header - The value of the Origin-Isolation header that the
+ *   iframe will set. Omit this to set no header.
+ * @returns {HTMLIFrameElement} The created iframe element
+ */
+export async function insertIframe(hostname, header) {
   const iframe = document.createElement("iframe");
   const navigatePromise = navigateIframe(iframe, hostname, header);
   document.body.append(iframe);
-  return navigatePromise;
+  await navigatePromise;
+  await setBothDocumentDomains(iframe.contentWindow);
+  return iframe;
 }
 
+/**
+ * Navigates an iframe to a page for origin isolation testing, similar to
+ * insertIframe but operating on an existing iframe.
+ * @param {HTMLIFrameElement} iframeEl - The <iframe> element to navigate
+ * @param {string} hostname - The hostname used to calculate the iframe's new
+ *   src=""
+ * @param {string=} header - The value of the Origin-Isolation header that the
+ *   newly-navigated-to page will set. Omit this to set no header.
+ * @returns {Promise} a promise fulfilled when the load event fires, or rejected
+ *   if the error event fires
+ */
 export function navigateIframe(iframeEl, hostname, header) {
-  const url = getURL(hostname, header);
+  const url = getIframeURL(hostname, header);
 
   const waitPromise = waitForIframe(iframeEl, url);
   iframeEl.src = url;
   return waitPromise;
 }
 
+/**
+ * Returns a promise that is fulfilled when an iframe's load event fires, or
+ * rejected when its error event fires.
+ * @param {HTMLIFrameElement} iframeEl - The <iframe> element to wait on
+ * @param {string} destinationForErrorMessage - A string used in the promise
+ *   rejection error message, if the error event fires
+ * @returns {Promise} a promise fulfilled when the load event fires, or rejected
+ *   if the error event fires
+ */
 export function waitForIframe(iframeEl, destinationForErrorMessage) {
   return new Promise((resolve, reject) => {
-    iframeEl.addEventListener("load", () => resolve(iframeEl.contentWindow));
+    iframeEl.addEventListener("load", () => resolve());
     iframeEl.addEventListener(
       "error",
       () => reject(new Error(`Could not navigate to ${destinationForErrorMessage}`))
@@ -23,7 +55,141 @@ export function waitForIframe(iframeEl, destinationForErrorMessage) {
   });
 }
 
-function getURL(hostname, header) {
+/**
+ * Expands into a pair of promise_test() calls to ensure that two Windows are in
+ * the same agent cluster, by checking both that we can send a
+ * WebAssembly.Module, and that we can synchronously access the DOM.
+ * @param {Array} testFrames - An array of either the form [self, frameIndex] or
+ *   [frameIndex1, frameIndex2], indicating the two Windows under test. E.g.
+ *   [self, 0] or [0, 1].
+ * @param {string=} testLabelPrefix - A prefix used in the test names. This can
+ *   be omitted if testSameAgentCluster is only used once in a test file.
+ */
+export function testSameAgentCluster(testFrames, testLabelPrefix) {
+  const prefix = testLabelPrefix === undefined ? "" : `${testLabelPrefix}: `;
+
+  if (testFrames[0] === self) {
+    // Between parent and a child at the index given by testFrames[1]
+
+    promise_test(async () => {
+      const frameWindow = frames[testFrames[1]];
+      const whatHappened = await sendWasmModule(frameWindow);
+
+      assert_equals(whatHappened, "WebAssembly.Module message received");
+    }, `${prefix}message event must occur`);
+
+    promise_test(async () => {
+      const frameWindow = frames[testFrames[1]];
+
+      // Must not throw
+      frameWindow.document;
+    }, `${prefix}setting document.domain must give sync access`);
+  } else {
+    // Between the two children at the index given by testFrames[0] and
+    // testFrames[1]
+
+    promise_test(async () => {
+      const whatHappened = await sendWasmModuleBetween(testFrames);
+
+      assert_equals(whatHappened, "WebAssembly.Module message received");
+    }, `${prefix}message event must occur`);
+
+    promise_test(async () => {
+      const whatHappened = await accessDocumentBetween(testFrames);
+
+      assert_equals(whatHappened, "accessed document successfully");
+    }, `${prefix}setting document.domain must give sync access`);
+  }
+}
+
+/**
+ * Expands into a pair of promise_test() calls to ensure that two Windows are in
+ * different agent clusters, by checking both that we cannot send a
+ * WebAssembly.Module, and that we cannot synchronously access the DOM.
+ * @param {Array} testFrames - An array of either the form [self, frameIndex] or
+ *   [frameIndex1, frameIndex2], indicating the two Windows under test. E.g.
+ *   [self, 0] or [0, 1].
+ * @param {string=} testLabelPrefix - A prefix used in the test names. This can
+ *   be omitted if testDifferentAgentClusters is only used once in a test file.
+ */
+export function testDifferentAgentClusters(testFrames, testLabelPrefix) {
+  const prefix = testLabelPrefix === undefined ? "" : `${testLabelPrefix}: `;
+
+  if (testFrames[0] === self) {
+    // Between parent and a child at the index given by testFrames[1]
+
+    promise_test(async () => {
+      const frameWindow = frames[testFrames[1]];
+      const whatHappened = await sendWasmModule(frameWindow);
+
+      assert_equals(whatHappened, "messageerror");
+    }, `${prefix}messageerror event must occur`);
+
+    promise_test(async () => {
+      const frameWindow = frames[testFrames[1]];
+
+      assert_throws_dom("SecurityError", DOMException, () => {
+        frameWindow.document;
+      });
+    }, `${prefix}setting document.domain must not give sync access`);
+  } else {
+    // Between the two children at the index given by testFrames[0] and
+    // testFrames[1]
+
+    promise_test(async () => {
+      const whatHappened = await sendWasmModuleBetween(testFrames);
+
+      assert_equals(whatHappened, "messageerror");
+    }, `${prefix}messageerror event must occur`);
+
+    promise_test(async () => {
+      const whatHappened = await accessDocumentBetween(testFrames);
+
+      assert_equals(whatHappened, "SecurityError");
+    }, `${prefix}setting document.domain must not give sync access`);
+  }
+}
+
+/**
+ * Sends a WebAssembly.Module instance to the given Window, and waits for it to
+ * send back a message indicating whether it got the module or got a
+ * messageerror event. (This relies on the given Window being derived from
+ * insertIframe or navigateIframe.)
+ * @param {Window} frameWindow - The destination Window
+ * @returns {Promise} A promise which will be fulfilled with either
+ *   "WebAssembly.Module message received" or "messageerror"
+ */
+export async function sendWasmModule(frameWindow) {
+  // This function is coupled to ./send-origin-isolation-header.py, which ensures
+  // that sending such a message will result in a message back.
+  frameWindow.postMessage(await createWasmModule(), "*");
+  return waitForMessage(frameWindow);
+}
+
+/**
+ * Sets document.domain (to itself) for both the current Window and the given
+ * Window. The latter relies on the given Window being derived from insertIframe
+ * or navigateIframe.
+ * @param frameWindow - The other Window whose document.domain is to be set
+ * @returns {Promise} A promise which will be fulfilled after both
+ *   document.domains are set
+ */
+export async function setBothDocumentDomains(frameWindow) {
+  // By setting both this page's document.domain and the iframe's
+  // document.domain to the same value, we ensure that they can synchronously
+  // access each other, unless they are origin-isolated.
+  // NOTE: document.domain being unset is different than it being set to its
+  // current value. It is a terrible API.
+  document.domain = document.domain;
+
+  // This function is coupled to ./send-origin-isolation-header.py, which ensures
+  // that sending such a message will result in a message back.
+  frameWindow.postMessage({ command: "set document.domain", newDocumentDomain: document.domain }, "*");
+  const whatHappened = await waitForMessage(frameWindow);
+  assert_equals(whatHappened, "document.domain is set");
+}
+
+function getIframeURL(hostname, header) {
   const url = new URL("send-origin-isolation-header.py", import.meta.url);
   url.hostname = hostname;
   if (header !== undefined) {
@@ -33,36 +199,20 @@ function getURL(hostname, header) {
   return url.href;
 }
 
-// This function is coupled to ./send-origin-isolation-header.py, which ensures
-// that sending such a message will result in a message back.
-export async function sendWasmModule(frameWindow) {
-  frameWindow.postMessage(await createWasmModule(), "*");
-  return waitForMessage(frameWindow);
+async function sendWasmModuleBetween(testFrames) {
+  const sourceFrame = frames[testFrames[0]];
+  const indexIntoParentFrameOfDestination = testFrames[1];
+
+  sourceFrame.postMessage({ command: "send WASM module", indexIntoParentFrameOfDestination }, "*");
+  return waitForMessage(sourceFrame);
 }
 
-export async function sendWasmModuleBetween(frameWindow, indexIntoParentFrameOfDestination) {
-  frameWindow.postMessage({ command: "send WASM module", indexIntoParentFrameOfDestination }, "*");
-  return waitForMessage(frameWindow);
-}
+async function accessDocumentBetween(testFrames) {
+  const sourceFrame = frames[testFrames[0]];
+  const indexIntoParentFrameOfDestination = testFrames[1];
 
-export async function accessDocumentBetween(frameWindow, indexIntoParentFrameOfDestination) {
-  frameWindow.postMessage({ command: "access document", indexIntoParentFrameOfDestination }, "*");
-  return waitForMessage(frameWindow);
-}
-
-// This function is coupled to ./send-origin-isolation-header.py, which ensures
-// that sending such a message will result in a message back.
-export async function setBothDocumentDomains(frameWindow) {
-  // By setting both this page's document.domain and the iframe's document.domain to the same
-  // value, we ensure that they can synchronously access each other, unless they are
-  // origin-isolated.
-  // NOTE: document.domain being unset is different than it being set to its current value.
-  // It is a terrible API.
-  document.domain = document.domain;
-
-  frameWindow.postMessage({ command: "set document.domain", newDocumentDomain: document.domain }, "*");
-  const whatHappened = await waitForMessage(frameWindow);
-  assert_equals(whatHappened, "document.domain is set");
+  sourceFrame.postMessage({ command: "access document", indexIntoParentFrameOfDestination }, "*");
+  return waitForMessage(sourceFrame);
 }
 
 function waitForMessage(expectedSource) {
@@ -77,8 +227,8 @@ function waitForMessage(expectedSource) {
   });
 }
 
-// Any WebAssembly.Module will work fine for our tests; we just want to find out if it gives
-// message or messageerror. So, we reuse one from the /wasm/ tests.
+// Any WebAssembly.Module will work fine for our tests; we just want to find out
+// if it gives message or messageerror. So, we reuse one from the /wasm/ tests.
 async function createWasmModule() {
   const response = await fetch("/wasm/serialization/module/resources/incrementer.wasm");
   const ab = await response.arrayBuffer();
diff --git a/tests/wpt/web-platform-tests/resources/chromium/mock-screenenumeration.js b/tests/wpt/web-platform-tests/resources/chromium/mock-screenenumeration.js
index 0f71db8f506..b655d1863cb 100644
--- a/tests/wpt/web-platform-tests/resources/chromium/mock-screenenumeration.js
+++ b/tests/wpt/web-platform-tests/resources/chromium/mock-screenenumeration.js
@@ -33,6 +33,13 @@ var ScreenEnumerationTest = (() => {
       this.displays_.push(display);
     }
 
+    removeDisplay(id) {
+      for (var i = 0; i < this.displays_.length; i++) {
+        if (this.displays_[i].id === id)
+          this.displays_.splice(i,1);
+      }
+    }
+
     async getDisplays() {
       return Promise.resolve({
         displays: this.displays_,
diff --git a/tests/wpt/web-platform-tests/screen_enumeration/README.md b/tests/wpt/web-platform-tests/screen_enumeration/README.md
index 04b2ecce7c2..b2d39f534ac 100644
--- a/tests/wpt/web-platform-tests/screen_enumeration/README.md
+++ b/tests/wpt/web-platform-tests/screen_enumeration/README.md
@@ -16,6 +16,7 @@ The `ScreenEnumerationTest` interface is defined as:
     setId(internalId, primaryId); // Set primary screen and internal screen IDs.
     setSuccess(success); // Set boolean to validate getDisplays() returned values.
     addDisplay(display); // Push display to the display vector.
+    removeDisplay(id); // Remove display from the display vector.
     async getDisplays(); // Interceptor of getDisplays (screen_enumeration.mojom).
   };
 ```
diff --git a/tests/wpt/web-platform-tests/screen_enumeration/getScreens.values.https.html b/tests/wpt/web-platform-tests/screen_enumeration/getScreens.values.https.html
index 5ce54839dee..3d70a7c81cf 100644
--- a/tests/wpt/web-platform-tests/screen_enumeration/getScreens.values.https.html
+++ b/tests/wpt/web-platform-tests/screen_enumeration/getScreens.values.https.html
@@ -23,7 +23,7 @@ screen_enumeration_test(async (t, mockScreenEnum) => {
   // Grant window-placement permissions for testdriver.
   await test_driver.set_permission({name: "window-placement"}, "granted");
 
-  // This call is calling GetDisplays, which should fall in interceptor.
+  // This returns the mocked displays via MockScreenEnumeration implementation.
   const screens = await self.getScreens();
 
   assert_equals(screens.length, 1);
@@ -41,4 +41,52 @@ screen_enumeration_test(async (t, mockScreenEnum) => {
   assert_equals(screens[0].scaleFactor, 1.0);
   assert_equals(screens[0].id, "0");
 }, "getScreens() returns a single mocked screen");
+
+screen_enumeration_test(async (t, mockScreenEnum) => {
+  let display1 = makeDisplay(10,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  let display2 = makeDisplay(11,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  let display3 = makeDisplay(12,
+                             {x: 0, y: 10, width: 1200, height: 800},
+                             {x: 20, y: 30, width: 1000, height: 600},
+                             1.0);
+
+  mockScreenEnum.addDisplay(display1);
+  mockScreenEnum.addDisplay(display2);
+  mockScreenEnum.addDisplay(display3);
+  mockScreenEnum.setIds(mockScreenEnum.displays_[0].id, mockScreenEnum.displays_[0].id);
+  mockScreenEnum.setSuccess(true);
+
+  // Grant window-placement permissions for testdriver.
+  await test_driver.set_permission({name: "window-placement"}, "granted");
+
+  // This returns the mocked displays via MockScreenEnumeration implementation.
+  let screens = await self.getScreens();
+
+  assert_equals(screens.length, 3);
+  assert_equals(screens[0].id, "0");
+  assert_equals(screens[1].id, "1");
+  assert_equals(screens[2].id, "2");
+
+  mockScreenEnum.removeDisplay(display2.id);
+
+  screens = await self.getScreens();
+  assert_equals(screens.length, 2);
+  assert_equals(screens[0].id, "0");
+  assert_equals(screens[1].id, "1");
+
+  mockScreenEnum.removeDisplay(display1.id);
+
+  screens = await self.getScreens();
+  assert_equals(screens.length, 1);
+  assert_equals(screens[0].id, "0");
+}, "getScreens() supports multiple mocked screens");
+
 </script>
diff --git a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html
new file mode 100644
index 00000000000..e000ab124fe
--- /dev/null
+++ b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html
@@ -0,0 +1,55 @@
+<!doctype html>
+<title>Test consistency of processing after resume()</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script>
+const get_node_and_reply = (context) => {
+  const node = new AudioWorkletNode(context, 'port-processor');
+  return new Promise((resolve) => {
+    node.port.onmessage = (event) => resolve({node: node, reply: event.data});
+  });
+};
+const ping_for_reply = (node) => {
+  return new Promise((resolve) => {
+    node.port.onmessage = (event) => resolve(event.data);
+    node.port.postMessage('ping');
+  });
+};
+const assert_consistent = (constructReply, pong, expectedPongTime, name) => {
+  const blockSize = 128;
+  assert_equals(pong.timeStamp, expectedPongTime, `${name} pong time`);
+  assert_equals(pong.processCallCount * blockSize,
+                pong.currentFrame - constructReply.currentFrame,
+                `${name} processed frame count`);
+};
+const modulePath = '/webaudio/the-audio-api/' +
+    'the-audioworklet-interface/processors/port-processor.js';
+
+promise_test(async () => {
+  const realtime = new AudioContext();
+  await realtime.audioWorklet.addModule(modulePath);
+  await realtime.suspend();
+  const timeBeforeResume = realtime.currentTime;
+  // Two AudioWorkletNodes are constructed.
+  // node1 is constructed before and node2 after the resume() call.
+  const construct1 = get_node_and_reply(realtime);
+  const resume = realtime.resume();
+  const construct2 = get_node_and_reply(realtime);
+  const {node: node1, reply: constructReply1} = await construct1;
+  assert_equals(constructReply1.timeStamp, timeBeforeResume,
+                'construct time before resume');
+  const {node: node2, reply: constructReply2} = await construct2;
+  assert_greater_than_equal(constructReply2.timeStamp, timeBeforeResume,
+                'construct time after resume');
+  await resume;
+  // Suspend the context to freeze time and check that the processing for each
+  // node matches the elapsed time.
+  await realtime.suspend();
+  const timeAfterSuspend = realtime.currentTime;
+  const pong1 = await ping_for_reply(node1);
+  const pong2 = await ping_for_reply(node2);
+  assert_consistent(constructReply1, pong1, timeAfterSuspend, 'node1');
+  assert_consistent(constructReply2, pong2, timeAfterSuspend, 'node2');
+  assert_equals(pong1.currentFrame, pong2.currentFrame, 'currentFrame matches');
+});
+</script>
diff --git a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html
new file mode 100644
index 00000000000..596a825c3db
--- /dev/null
+++ b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/suspend-after-construct.html
@@ -0,0 +1,72 @@
+<!doctype html>
+<title>Test AudioContext state updates with suspend() shortly after
+  construction</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script>
+// A separate async_test is used for tracking state change counts so that it
+// can report excess changes after the promise_test for the iteration has
+// completed.
+const changeCountingTest = async_test('State change counting');
+
+const doTest = async (testCount) => {
+  const ctx = new AudioContext();
+  // Explicitly resume to get a promise to indicate whether the context
+  // successfully started running.
+  const resume = ctx.resume();
+  const suspend = ctx.suspend();
+  let stateChangesDone = new Promise((resolve) => {
+    ctx.onstatechange = () => {
+      ++ctx.stateChangeCount;
+      changeCountingTest.step(() => {
+        assert_less_than_equal(ctx.stateChangeCount,
+                               ctx.expectedStateChangeCount,
+                               `ctx ${testCount} state change count.`);
+        assert_equals(ctx.state, ctx.expectedState, `ctx ${testCount} state`);
+      });
+      if (ctx.stateChangeCount == ctx.totalStateChangeCount) {
+        resolve();
+      }
+    };
+  });
+  ctx.stateChangeCount = 0;
+  ctx.expectedStateChangeCount = 1;
+  ctx.expectedState = 'running';
+  ctx.totalStateChangeCount = 2;
+  let resumeState = 'pending';
+  resume.then(() => {
+    resumeState = 'fulfilled';
+    assert_equals(ctx.state, 'running', 'state on resume fulfilled.');
+  }).catch(() => {
+    // The resume() promise may be rejected if "Attempt to acquire system
+    // resources" fails.  The spec does not discuss the possibility of a
+    // subsequent suspend causing such a failure, but accept this as a
+    // reasonable behavior.
+    resumeState = 'rejected';
+    assert_equals(ctx.state, 'suspended', 'state on resume rejected.');
+    assert_equals(ctx.stateChangeCount, 0);
+    ctx.expectedStateChangeCount = 0;
+    stateChangesDone = Promise.resolve();
+  });
+  suspend.then(() => {
+    assert_not_equals(resumeState, 'pending',
+                      'resume promise should settle before suspend promise.')
+    if (resumeState == 'fulfilled') {
+      ++ctx.expectedStateChangeCount;
+    }
+    ctx.expectedState = 'suspended';
+    assert_equals(ctx.state, 'suspended', 'state on suspend fulfilled.');
+  });
+  await resume;
+  await suspend;
+  await stateChangesDone;
+};
+
+// Repeat the test because Gecko uses different code when there is more than
+// one AudioContext.  The third run provides time to check that no further
+// state changes from the second run are pending.
+for (const testCount of [1, 2, 3]) {
+  promise_test(() => { return doTest(testCount); }, `Iteration ${testCount}`);
+}
+promise_test(async () => changeCountingTest.done(), 'Stop waiting');
+</script>
diff --git a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/processors/port-processor.js b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/processors/port-processor.js
index 5a8baf03372..8def5a61d7e 100644
--- a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/processors/port-processor.js
+++ b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/processors/port-processor.js
@@ -10,18 +10,23 @@ class PortProcessor extends AudioWorkletProcessor {
     this.port.onmessage = this.handleMessage.bind(this);
     this.port.postMessage({
       state: 'created',
-      timeStamp: currentTime
+      timeStamp: currentTime,
+      currentFrame: currentFrame
     });
+    this.processCallCount = 0;
   }
 
   handleMessage(event) {
     this.port.postMessage({
       message: event.data,
-      timeStamp: currentTime
+      timeStamp: currentTime,
+      currentFrame: currentFrame,
+      processCallCount: this.processCallCount
     });
   }
 
   process() {
+    ++this.processCallCount;
     return true;
   }
 }
diff --git a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/suspended-context-messageport.https.html b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/suspended-context-messageport.https.html
index 5f5b10a251f..f6fa6ddd986 100644
--- a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/suspended-context-messageport.https.html
+++ b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioworklet-interface/suspended-context-messageport.https.html
@@ -3,13 +3,13 @@
 <script src=/resources/testharness.js></script>
 <script src=/resources/testharnessreport.js></script>
 <script>
-const get_node_and_message = async (context) => {
+const get_node_and_message = (context) => {
   const node = new AudioWorkletNode(context, 'port-processor');
   return new Promise((resolve) => {
     node.port.onmessage = (event) => resolve({node: node, event: event});
   });
 };
-const ping_for_message = async (node) => {
+const ping_for_message = (node) => {
   return new Promise((resolve) => {
     node.port.onmessage = resolve;
     node.port.postMessage('ping');
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-helper.js b/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-helper.js
index 531a8a7f4ff..07626bd0ccc 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-helper.js
+++ b/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-helper.js
@@ -190,117 +190,58 @@ function exchangeIceCandidates(pc1, pc2) {
   doExchange(pc2, pc1);
 }
 
-// Returns a promise that resolves when the |transport| gets a
-// 'statechange' event with the value |state|.
-// This should work for RTCSctpTransport, RTCDtlsTransport and RTCIceTransport.
-function waitForState(transport, state) {
-  return new Promise((resolve, reject) => {
-    if (transport.state == state) {
-      resolve();
-    }
-    const eventHandler = () => {
-      if (transport.state == state) {
-        transport.removeEventListener('statechange', eventHandler, false);
-        resolve();
-      }
-    };
-    transport.addEventListener('statechange', eventHandler, false);
-  });
+// Returns a promise that resolves when a |name| event is fired.
+function waitUntilEvent(obj, name) {
+  return new Promise(r => obj.addEventListener(name, r, {once: true}));
 }
 
+// Returns a promise that resolves when the |transport.state| is |state|
+// This should work for RTCSctpTransport, RTCDtlsTransport and RTCIceTransport.
+async function waitForState(transport, state) {
+  while (transport.state != state) {
+    await waitUntilEvent(transport, 'statechange');
+  }
+}
 
 // Returns a promise that resolves when |pc.iceConnectionState| is 'connected'
 // or 'completed'.
-function listenToIceConnected(pc) {
-  return new Promise((resolve) => {
-    function isConnected(pc) {
-      return pc.iceConnectionState == 'connected' ||
-            pc.iceConnectionState == 'completed';
-    }
-    if (isConnected(pc)) {
-      resolve();
-      return;
-    }
-    pc.addEventListener('iceconnectionstatechange', () => {
-      if (isConnected(pc))
-        resolve();
-    });
-  });
+async function listenToIceConnected(pc) {
+  await waitForIceStateChange(pc, ['connected', 'completed']);
 }
 
 // Returns a promise that resolves when |pc.iceConnectionState| is in one of the
 // wanted states.
-function waitForIceStateChange(pc, wantedStates) {
-  return new Promise((resolve) => {
-    if (wantedStates.includes(pc.iceConnectionState)) {
-      resolve();
-      return;
-    }
-    pc.addEventListener('iceconnectionstatechange', () => {
-      if (wantedStates.includes(pc.iceConnectionState))
-        resolve();
-    });
-  });
+async function waitForIceStateChange(pc, wantedStates) {
+  while (!wantedStates.includes(pc.iceConnectionState)) {
+    await waitUntilEvent(pc, 'iceconnectionstatechange');
+  }
 }
 
 // Returns a promise that resolves when |pc.connectionState| is 'connected'.
-function listenToConnected(pc) {
-  return new Promise((resolve) => {
-    if (pc.connectionState == 'connected') {
-      resolve();
-      return;
-    }
-    pc.onconnectionstatechange = () => {
-      if (pc.connectionState == 'connected')
-        resolve();
-    };
-  });
+async function listenToConnected(pc) {
+  while (pc.connectionState != 'connected') {
+    await waitUntilEvent(pc, 'connectionstatechange');
+  }
 }
 
 // Returns a promise that resolves when |pc.connectionState| is in one of the
 // wanted states.
-function waitForConnectionStateChange(pc, wantedStates) {
-  return new Promise((resolve) => {
-    if (wantedStates.includes(pc.connectionState)) {
-      resolve();
-      return;
-    }
-    pc.addEventListener('connectionstatechange', () => {
-      if (wantedStates.includes(pc.connectionState))
-        resolve();
-    });
-  });
-}
-
-// Returns a promise that resolves when |pc.connectionState| is in one of the
-// wanted states.
-function waitForConnectionStateChange(pc, wantedStates) {
-  return new Promise((resolve) => {
-    if (wantedStates.includes(pc.connectionState)) {
-      resolve();
-      return;
-    }
-    pc.addEventListener('connectionstatechange', () => {
-      if (wantedStates.includes(pc.connectionState))
-        resolve();
-    });
-  });
+async function waitForConnectionStateChange(pc, wantedStates) {
+  while (!wantedStates.includes(pc.connectionState)) {
+    await waitUntilEvent(pc, 'connectionstatechange');
+  }
 }
 
 // Resolves when RTP packets have been received.
-function listenForSSRCs(t, receiver) {
-  return new Promise((resolve) => {
-    function listen() {
-      const ssrcs = receiver.getSynchronizationSources();
-      assert_true(ssrcs != undefined);
-      if (ssrcs.length > 0) {
-        resolve(ssrcs);
-        return;
-      }
-      t.step_timeout(listen, 0);
-    };
-    listen();
-  });
+async function listenForSSRCs(t, receiver) {
+  while (true) {
+    const ssrcs = receiver.getSynchronizationSources();
+    assert_true(Array.isArray(ssrcs));
+    if (ssrcs.length > 0) {
+      return ssrcs;
+    }
+    await new Promise(r => t.step_timeout(r, 0));
+  }
 }
 
 // Helper function to create a pair of connected data channels.
@@ -365,28 +306,21 @@ async function waitForRtpAndRtcpStats(pc) {
 // Wait for a single message event and return
 // a promise that resolve when the event fires
 function awaitMessage(channel) {
+  const once = true;
   return new Promise((resolve, reject) => {
-    channel.addEventListener('message',
-      event => resolve(event.data),
-      { once: true });
-
-    channel.addEventListener('error', reject, { once: true });
+    channel.addEventListener('message', ({data}) => resolve(data), {once});
+    channel.addEventListener('error', reject, {once});
   });
 }
 
 // Helper to convert a blob to array buffer so that
 // we can read the content
-function blobToArrayBuffer(blob) {
+async function blobToArrayBuffer(blob) {
+  const reader = new FileReader();
+  reader.readAsArrayBuffer(blob);
   return new Promise((resolve, reject) => {
-    const reader = new FileReader();
-
-    reader.addEventListener('load', () => {
-      resolve(reader.result);
-    });
-
-    reader.addEventListener('error', reject);
-
-    reader.readAsArrayBuffer(blob);
+    reader.addEventListener('load', () => resolve(reader.result), {once: true});
+    reader.addEventListener('error', () => reject(reader.error), {once: true});
   });
 }
 
@@ -495,30 +429,28 @@ function getVideoSignal(v) {
   if (v.videoWidth < 21 || v.videoHeight < 21) {
     return null;
   }
-  const canvas = new OffscreenCanvas(v.videoWidth, v.videoHeight);
-  let context = canvas.getContext('2d');
+  const canvas = document.createElement("canvas");
+  canvas.width = v.videoWidth;
+  canvas.height = v.videoHeight;
+  const context = canvas.getContext('2d');
   context.drawImage(v, 0, 0, v.videoWidth, v.videoHeight);
   // Extract pixel value at position 20, 20
-  let pixel = context.getImageData(20, 20, 1, 1);
+  const pixel = context.getImageData(20, 20, 1, 1);
   // Use luma reconstruction to get back original value according to
   // ITU-R rec BT.709
   return (pixel.data[0] * 0.21 + pixel.data[1] * 0.72 + pixel.data[2] * 0.07);
 }
 
-function detectSignal(t, v, value) {
-  return new Promise((resolve) => {
-    let check = () => {
-      const signal = getVideoSignal(v);
-      if (signal !== null && signal < value + 1 && signal > value - 1) {
-        resolve();
-      } else {
-        // We would like to wait for each new frame instead here,
-        // but there seems to be no such callback.
-        t.step_timeout(check, 100);
-      }
+async function detectSignal(t, v, value) {
+  while (true) {
+    const signal = getVideoSignal(v);
+    if (signal !== null && signal < value + 1 && signal > value - 1) {
+      return;
     }
-    check();
-  });
+    // We would like to wait for each new frame instead here,
+    // but there seems to be no such callback.
+    await new Promise(r => t.step_timeout(r, 100));
+  }
 }
 
 // Generate a MediaStream bearing the specified tracks.
@@ -652,14 +584,13 @@ class Resolver extends Promise {
   }
 }
 
-function addEventListenerPromise(t, target, type, listener) {
-  return new Promise((resolve, reject) => {
-    target.addEventListener(type, t.step_func(e => {
-      if (listener != undefined)
-        e = listener(e);
-      resolve(e);
-    }));
-  });
+function addEventListenerPromise(t, obj, type, listener) {
+  if (!listener) {
+    return waitUntilEvent(obj, type);
+  }
+  return new Promise(r => obj.addEventListener(type,
+                                               t.step_func(e => r(listener(e))),
+                                               {once: true}));
 }
 
 function createPeerConnectionWithCleanup(t) {
diff --git a/tests/wpt/webgl/meta/conformance/textures/misc/texture-size-limit.html.ini b/tests/wpt/webgl/meta/conformance/textures/misc/texture-size-limit.html.ini
index 2e1cb39c595..93258ecfc74 100644
--- a/tests/wpt/webgl/meta/conformance/textures/misc/texture-size-limit.html.ini
+++ b/tests/wpt/webgl/meta/conformance/textures/misc/texture-size-limit.html.ini
@@ -1,2 +1,2 @@
 [texture-size-limit.html]
-  expected: TIMEOUT
+  expected: CRASH