diff --git a/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini b/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini
deleted file mode 100644
index a9005e45d6e..00000000000
--- a/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[url-charset.window.html]
-  expected: TIMEOUT
-  [Blob charset should override any auto-detected charset.]
-    expected: TIMEOUT
-
-  [Blob charset should override <meta charset>.]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini
deleted file mode 100644
index baa9f1a7541..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-005.html]
-  [Miss clipped float]
-    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 2469a7e1361..bbf756d71c5 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
@@ -312,18 +312,27 @@
   [<iframe>: separate response Content-Type: text/plain */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html;x=" text/plain]
-    expected: FAIL
-
-  [<iframe>: separate response Content-Type: text/html;" text/plain]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
   [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
     expected: FAIL
 
+  [<iframe>: combined response Content-Type: text/html;" text/plain]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: */* text/html]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;x=" text/plain]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+    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 8d0261f22a0..b2ffc8abf78 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
@@ -56,6 +56,6 @@
   [separate text/javascript x/x]
     expected: FAIL
 
-  [separate text/javascript; charset=windows-1252 text/javascript]
+  [separate text/javascript error]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/fetch/h1-parsing/status-code.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/h1-parsing/status-code.window.js.ini
new file mode 100644
index 00000000000..90f03418df6
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/fetch/h1-parsing/status-code.window.js.ini
@@ -0,0 +1,22 @@
+[status-code.window.html]
+  [HTTP/1.1 999 DOES IT MATTER ]
+    expected: FAIL
+
+  [HTTP/1.1 077 77 ]
+    expected: FAIL
+
+  [HTTP/1.1 200 ]
+    expected: FAIL
+
+  [HTTP/1.1 1 OK ]
+    expected: FAIL
+
+  [HTTP/1.1 099 HELLO ]
+    expected: FAIL
+
+  [HTTP/1.1 99 NOT OK ]
+    expected: FAIL
+
+  [HTTP/1.1 0 OK ]
+    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/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
similarity index 71%
rename from tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
rename to tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
index 51f8272a6de..dc2e45516de 100644
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_3.html]
+[traverse_the_history_5.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
deleted file mode 100644
index 735a9a75a2a..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[cross-origin-objects-on-new-window.html]
-  expected: TIMEOUT
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_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 3080be9afc0..d913fcbb129 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
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_nonescaping-1.html]
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/forms/textfieldselection/select-event.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/forms/textfieldselection/select-event.html.ini
index 7e0021a4d8f..4a713856a76 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/forms/textfieldselection/select-event.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/forms/textfieldselection/select-event.html.ini
@@ -1,19 +1,10 @@
 [select-event.html]
-  [input type search: setRangeText() a second time (must not fire select)]
-    expected: FAIL
-
   [input type text: selectionEnd a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: setRangeText() a second time (must not fire select)]
-    expected: FAIL
-
   [input type password: select() a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: selectionStart out of range a second time (must not fire select)]
-    expected: FAIL
-
   [input type search: selectionEnd a second time (must not fire select)]
     expected: FAIL
 
@@ -26,36 +17,57 @@
   [input type password: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: setSelectionRange out of range a second time (must not fire select)]
-    expected: FAIL
-
-  [input type tel: selectionEnd out of range a second time (must not fire select)]
-    expected: FAIL
-
   [textarea: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: selectionEnd a second time (must not fire select)]
-    expected: FAIL
-
-  [input type password: selectionEnd out of range a second time (must not fire select)]
-    expected: FAIL
-
   [textarea: setSelectionRange() a second time (must not fire select)]
     expected: FAIL
 
-  [input type tel: setSelectionRange() a second time (must not fire select)]
-    expected: FAIL
-
   [input type url: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
   [input type text: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type text: selectionStart out of range a second time (must not fire select)]
-    expected: FAIL
-
   [input type search: selectionStart a second time (must not fire select)]
     expected: FAIL
 
+  [textarea: selectionEnd a second time (must not fire select)]
+    expected: FAIL
+
+  [input type tel: setRangeText() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type url: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: setSelectionRange out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: setSelectionRange out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: selectionStart out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: selectionEnd out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type password: setRangeText() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: selectionDirection a second time (must not fire select)]
+    expected: FAIL
+
+  [textarea: selectionStart out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type tel: selectionStart a second time (must not fire select)]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini
new file mode 100644
index 00000000000..59a54fe88e4
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini
@@ -0,0 +1,4 @@
+[module-delayed.html]
+  [async document.write in a module]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
deleted file mode 100644
index fca4d908c89..00000000000
--- a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[module-static-import-delayed.html]
-  [document.write in an imported module]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/referrer-policy/gen/iframe.meta/strict-origin/xhr.http.html.ini b/tests/wpt/metadata-layout-2020/referrer-policy/gen/iframe.meta/strict-origin/xhr.http.html.ini
new file mode 100644
index 00000000000..df949005d22
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/referrer-policy/gen/iframe.meta/strict-origin/xhr.http.html.ini
@@ -0,0 +1,2 @@
+[xhr.http.html]
+  expected: CRASH
diff --git a/tests/wpt/metadata/webdriver/tests/idlharness.html.ini b/tests/wpt/metadata-layout-2020/webdriver/tests/idlharness.window.js.ini
similarity index 87%
rename from tests/wpt/metadata/webdriver/tests/idlharness.html.ini
rename to tests/wpt/metadata-layout-2020/webdriver/tests/idlharness.window.js.ini
index 5283e8f30fa..f89cd1a148d 100644
--- a/tests/wpt/metadata/webdriver/tests/idlharness.html.ini
+++ b/tests/wpt/metadata-layout-2020/webdriver/tests/idlharness.window.js.ini
@@ -1,4 +1,4 @@
-[idlharness.html]
+[idlharness.window.html]
   [Navigator interface: navigator must inherit property "webdriver" with the proper type]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/webmessaging/without-ports/017.html.ini b/tests/wpt/metadata-layout-2020/webmessaging/without-ports/017.html.ini
deleted file mode 100644
index 064cf47545b..00000000000
--- a/tests/wpt/metadata-layout-2020/webmessaging/without-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/FileAPI/url/url-charset.window.js.ini b/tests/wpt/metadata/FileAPI/url/url-charset.window.js.ini
deleted file mode 100644
index a9005e45d6e..00000000000
--- a/tests/wpt/metadata/FileAPI/url/url-charset.window.js.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[url-charset.window.html]
-  expected: TIMEOUT
-  [Blob charset should override any auto-detected charset.]
-    expected: TIMEOUT
-
-  [Blob charset should override <meta charset>.]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index ad2972f6a64..7db34dde71f 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -149190,6 +149190,19 @@
        {}
       ]
      ],
+     "table-as-item-percent-width-cell-001.html": [
+      "b578b233405fdc164be5c26456f8bc1d558cf85c",
+      [
+       null,
+       [
+        [
+         "/css/css-flexbox/table-as-item-percent-width-cell-001-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "table-as-item-specified-width.html": [
       "a4b370eb254dd84eaa90fcc4a658d101b681655c",
       [
@@ -166249,6 +166262,19 @@
        {}
       ]
      ],
+     "multicol-breaking-006.html": [
+      "7efeee80251f6d912ff8d6ef1111e2fd6cf5b8a6",
+      [
+       null,
+       [
+        [
+         "/css/css-multicol/multicol-breaking-006-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "multicol-breaking-nobackground-000.html": [
       "768ec63298f03eb28a80a4e33f140314168b010d",
       [
@@ -177144,6 +177170,19 @@
        {}
       ]
      ],
+     "transparent-on-root.html": [
+      "fcab71127d3cd8b38c0843cedff1f10aa59bb7bf",
+      [
+       null,
+       [
+        [
+         "/css/css-scrollbars/transparent-on-root-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "viewport-scrollbar-body.html": [
       "a1b3aee871a918dc4e3f92e669d6631c0944cd18",
       [
@@ -259842,7 +259881,7 @@
   },
   "support": {
    ".azure-pipelines.yml": [
-    "1c9883ccdec0532499b8df805527ea8e8c37c32f",
+    "337d7e326ac920d67117924f5772e40b735c0248",
     []
    ],
    ".codecov.yml": [
@@ -307371,6 +307410,10 @@
        []
       ]
      },
+     "table-as-item-percent-width-cell-001-ref.html": [
+      "2f40b6c49fdcee593a160c82c381d4c14f377a38",
+      []
+     ],
      "table-item-flex-percentage-width-ref.html": [
       "e598475fddf54274f93609de94b0f950618bc8e2",
       []
@@ -317095,6 +317138,10 @@
       "a22fda57c0b2759cce0e1e6ce72de7c07c22ed23",
       []
      ],
+     "multicol-breaking-006-ref.html": [
+      "06e92eb8395b77ef33b5754a6743ec05c0159682",
+      []
+     ],
      "multicol-breaking-nobackground-000-ref.html": [
       "7a99354061cfeb982fffb921c850484dd02eac15",
       []
@@ -319629,6 +319676,10 @@
       "9f505dd7f1d121c0bd0af0131b51f536225326b1",
       []
      ],
+     "transparent-on-root-ref.html": [
+      "a5b2de4f00f3abd19c74b08b80a027d09a7abcca",
+      []
+     ],
      "viewport-scrollbar-body-ref.html": [
       "4e07903e2ca1e5d0378845c8cc4754dc82b1ebf8",
       []
@@ -334662,7 +334713,7 @@
       []
      ],
      "from-local-system.md": [
-      "f5cfa36915d7892d827d8f5aa74649e0e2c0c062",
+      "53f6a1fb98d58f900e34895a9461332512e8c06c",
       []
      ],
      "from-web.md": [
@@ -334724,7 +334775,7 @@
       []
      ],
      "h2tests.md": [
-      "c13295e1fe668af1ed9561463b2ec18719f8deb6",
+      "9a429373f567253b174ed6f7be85290d41b20dc3",
       []
      ],
      "idlharness.md": [
@@ -334736,7 +334787,7 @@
       []
      ],
      "lint-tool.md": [
-      "ba11169e020c8c74a2a4dab04c316d3e391321a1",
+      "95f8b574158e77f195b11060b19e67328f0029d2",
       []
      ],
      "making-a-testing-plan.md": [
@@ -334753,7 +334804,7 @@
      ],
      "python-handlers": {
       "index.md": [
-       "e4d396f90a796492323d8c1c878905267a62c617",
+       "96f7edb61601b1af1795d62cefd3bd5bc09c817b",
        []
       ]
      },
@@ -334770,7 +334821,7 @@
       []
      ],
      "server-features.md": [
-      "a1ba09132c5a40591321b0532dab1c3008987c2b",
+      "fe3e84836c21e31583ed1c5d244f8dc85a3cf7eb",
       []
      ],
      "server-pipes.md": [
@@ -338191,6 +338242,10 @@
       "script-with-0x00-in-header.py": [
        "39f58d8270e7671bf74e40ac84e05a7558df4f68",
        []
+      ],
+      "status-code.py": [
+       "5421893b26732e3c479731c322e4022980235d03",
+       []
       ]
      }
     },
@@ -356987,7 +357042,7 @@
      []
     ],
     "link-header-preload.html.headers": [
-     "293598ee66982baa00b92c9e64df6347190ab057",
+     "83758fb9cdc128d291b96c2a9a7e8abb3958dc64",
      []
     ],
     "preload-in-data-doc-ref.html": [
@@ -359118,7 +359173,7 @@
       []
      ],
      "generic_sensor_mocks.js": [
-      "85891c6ef129d31794404476d25878c7eb8c5bd7",
+      "56438824518225a9b1e5c89f1f6b73aa7f4e57c0",
       []
      ],
      "generic_sensor_mocks.js.headers": [
@@ -359211,7 +359266,7 @@
      ]
     },
     "idlharness.js": [
-     "5a97b273f2bed196d6ddd85c5596decff1bf87ae",
+     "76131e7c9602b94f9543d1f49658b304535691d3",
      []
     ],
     "idlharness.js.headers": [
@@ -364071,11 +364126,11 @@
        []
       ],
       "update_hosts.yml": [
-       "64aff7cf46a83e0ad0045065b5ec2e78deb6506d",
+       "63c7e45811297a2dd5342b3b3ab9093acab6f5cd",
        []
       ],
       "update_manifest.yml": [
-       "e8f28217f1eaa9af3ec67e2b1a64365c8aa87a81",
+       "453ac2ac3c05cf873bcf66d1be990324bd20036e",
        []
       ]
      },
@@ -364166,7 +364221,7 @@
       ],
       "tasks": {
        "test.yml": [
-        "b3a396068933661849e628ceeebb10f6a90be538",
+        "95212e97bf7961804ce01281c3023badcc7cd330",
         []
        ]
       },
@@ -364198,7 +364253,7 @@
         []
        ],
        "test_valid.py": [
-        "30fdfdc13d88ee05aa015fb7529f4a3e67aaedaf",
+        "9891e1cfc5d98d9e36c807f9b06df581bfbc7072",
         []
        ]
       }
@@ -364617,7 +364672,7 @@
      []
     ],
     "py3-flake8.ini": [
-     "14cc1dc6f6a7afb41f12c41fa8293337d19a023b",
+     "f8d4776ef66b01fac0bfa2d27320b1ea3f8a497f",
      []
     ],
     "pytest.ini": [
@@ -371804,7 +371859,7 @@
       []
      ],
      "install.py": [
-      "638065a53014f3d463269793aa08f3acf30654ea",
+      "8ba5c7a85916fcce1a1452b9ef002dca47a34bef",
       []
      ],
      "mach-emulator.manifest": [
@@ -371828,7 +371883,7 @@
       []
      ],
      "run.py": [
-      "3d380eab5cbdb00ffc612dedc595310f7d0e60a1",
+      "68f8e32ca1812974cd9eb42f48e6c34a9ad5b2b5",
       []
      ],
      "testfiles.py": [
@@ -372138,11 +372193,11 @@
         []
        ],
        "android_weblayer.py": [
-        "f68312f231bba4f08aba7defbc272a86e98af244",
+        "972e5517b1cff6d1635b35bef512f3589e22933e",
         []
        ],
        "android_webview.py": [
-        "3cde248b4465cd10a86a813de8551808c42dbf18",
+        "918a881b908ddcdaec1954110cdb99e71845f362",
         []
        ],
        "base.py": [
@@ -372150,15 +372205,15 @@
         []
        ],
        "chrome.py": [
-        "d3e27a9c5f65f7aa754263cb57846285d2857540",
+        "04ac3726fba16d3ea315cbf24310cb69c5db8a61",
         []
        ],
        "chrome_android.py": [
-        "d7e3e21012169fdf12e47d3bc87552f46c779cf9",
+        "178183b4028393703c0e691f875531423cf86c60",
         []
        ],
        "chrome_ios.py": [
-        "ecdbc3a17623907dc9bd99505d1e5ee0bc747c7b",
+        "f349b19419cd67a3551ba1796e1ae02d2776e46d",
         []
        ],
        "chrome_spki_certs.py": [
@@ -372166,7 +372221,7 @@
         []
        ],
        "edge.py": [
-        "b908684bbb3e7eae9982173ed26a9a9e39b6b437",
+        "db4795ce5d4a773546b03782885d24a82337b031",
         []
        ],
        "edge_webdriver.py": [
@@ -372174,11 +372229,11 @@
         []
        ],
        "edgechromium.py": [
-        "1d45983a11ef0d3fdcfabd6e81fe2974ab2d68eb",
+        "c2275bd168797cc2486c138a8450a598c29891c9",
         []
        ],
        "epiphany.py": [
-        "a3384436a1d643c6576ebb731db5c458f8ad2687",
+        "f378170f33d33cc0839bf599fc1ac33dff7f0fe2",
         []
        ],
        "firefox.py": [
@@ -372190,19 +372245,19 @@
         []
        ],
        "ie.py": [
-        "3a86c1b6ccb5aabfe210158f6be613f690543375",
+        "5fce29a477070479a82126d318a93763d12b1c9b",
         []
        ],
        "opera.py": [
-        "a34f41955383c08e98c4d38d7804231c17e9297a",
+        "80e5a314c83b9866b350ff75375a48d153061624",
         []
        ],
        "safari.py": [
-        "312d4db9c6382f7aff5cd75772f0edf73e538565",
+        "0f62639c6350527fbfe69b65fb948c1d1e398844",
         []
        ],
        "sauce.py": [
-        "3497c5c277288e51f6677000e57057ebcd99a210",
+        "483bf206172a6c146a6b299742fb1ab85316b4d0",
         []
        ],
        "sauce_setup": {
@@ -372216,19 +372271,19 @@
         ]
        },
        "servo.py": [
-        "a65ed5ead4e55c45cfd7aa7921f0717216ce6a45",
+        "4f934aedfcd64153e77bb33efd9c6387832cfcec",
         []
        ],
        "servodriver.py": [
-        "ed85cbf3b9bd04ea192641b480ace44dc6d433bf",
+        "83b9423ba71a2d434b33156d624f64ffc6cc8515",
         []
        ],
        "webkit.py": [
-        "590e472aca961b865bf0dbc836c942f62b506ae8",
+        "f83de2996a98d75efcbaa66480b7cd210869a886",
         []
        ],
        "webkitgtk_minibrowser.py": [
-        "5b7a360fb608352e26971570af06c5bb8466255b",
+        "6c1001e2d70dcf55088b341978c8b30658f52c41",
         []
        ]
       },
@@ -372362,7 +372417,7 @@
         []
        ],
        "chromium.py": [
-        "2ff2bd1e083a3439d1289c9f540a8bb2b1e20dbc",
+        "b6cbb203a31ade463a809542c158b6ce859bcf5c",
         []
        ],
        "tests": {
@@ -372449,7 +372504,7 @@
        []
       ],
       "testrunner.py": [
-       "8dd93418dd8f37fc220306f7a4e6d85e7fb9b55a",
+       "0c658a158a3e4f170fe33a68702c2288801b2586",
        []
       ],
       "tests": {
@@ -396874,15 +396929,6 @@
       }
      ]
     ],
-    "async-idlharness.https.html": [
-     "a1a51c98690f1c83679c3ae71f3bafe99824f025",
-     [
-      null,
-      {
-       "timeout": "long"
-      }
-     ]
-    ],
     "async-navigator-clipboard-basics.https.html": [
      "61808a52ceb9b6272a6ce495d328a8feaaf9411a",
      [
@@ -397137,6 +397183,29 @@
       ]
      }
     },
+    "idlharness.https.window.js": [
+     "c22ee245442570af52087f22335b83d986ecb358",
+     [
+      "clipboard-apis/idlharness.https.window.html",
+      {
+       "script_metadata": [
+        [
+         "timeout",
+         "long"
+        ],
+        [
+         "script",
+         "/resources/WebIDLParser.js"
+        ],
+        [
+         "script",
+         "/resources/idlharness.js"
+        ]
+       ],
+       "timeout": "long"
+      }
+     ]
+    ],
     "permissions": {
      "readText-denied.https.html": [
       "935f520e7de2dd15e0019c798dd0966c454235cd",
@@ -402899,7 +402968,7 @@
      ]
     },
     "cookie-enabled-noncookie-frame.html": [
-     "539d715ebd5344de4cf02b6485462b31bc167525",
+     "2dbbc0bbdc5fbd4db19405a686c0b736aba08793",
      [
       null,
       {}
@@ -457097,6 +457166,13 @@
        "fetch/h1-parsing/resources-with-0x00-in-header.window.html",
        {}
       ]
+     ],
+     "status-code.window.js": [
+      "5776cf4050f01e838c42f7e845a2e033e2604f41",
+      [
+       "fetch/h1-parsing/status-code.window.html",
+       {}
+      ]
      ]
     },
     "http-cache": {
@@ -502972,6 +503048,13 @@
       {}
      ]
     ],
+    "transform-above-filter-dynamic.html": [
+     "1d7ed51a91652790d6f980af362a15fa546cc1de",
+     [
+      null,
+      {}
+     ]
+    ],
     "transform-above-perspective-dynamic.html": [
      "fea65ca56ad6bbca11c5eece6fa7a059668ecb31",
      [
@@ -503088,6 +503171,13 @@
       {}
      ]
     ],
+    "preloader-link-media.tentative.html": [
+     "0e58d8b6c890edfc494eca3775501f425a153c14",
+     [
+      null,
+      {}
+     ]
+    ],
     "preloader-template.tentative.html": [
      "e816309184844a6d46a20e1152c9efca80fe6f0b",
      [
@@ -513992,7 +514082,7 @@
      ]
     ],
     "pointerevent_capture_suppressing_mouse.html": [
-     "080ca1520d91ecd88264f0c501998cefc410edaf",
+     "b621dcb49a9e60b27c5ab599790136c06a4ef922",
      [
       null,
       {
@@ -515294,7 +515384,7 @@
      ]
     ],
     "link-header-preload.html": [
-     "b5932a1b0aa174f1fe8e28402595e681f39732be",
+     "8ad528d0e7c46cc7613461665f0eafed472f54c9",
      [
       null,
       {}
@@ -554199,11 +554289,22 @@
    },
    "webdriver": {
     "tests": {
-     "idlharness.html": [
-      "d049d835f2fc60df7296da08a013793ae7e398ca",
+     "idlharness.window.js": [
+      "e92e151d89836e06966339daabc6b1be50ded744",
       [
-       null,
-       {}
+       "webdriver/tests/idlharness.window.html",
+       {
+        "script_metadata": [
+         [
+          "script",
+          "/resources/WebIDLParser.js"
+         ],
+         [
+          "script",
+          "/resources/idlharness.js"
+         ]
+        ]
+       }
       ]
      ]
     }
@@ -565838,11 +565939,37 @@
       {}
      ]
     ],
-    "idlharness.worker.js": [
-     "827dd02c4c53292b534677454c11264f415678a5",
+    "idlharness.https.any.js": [
+     "2900b3812496ca430b15b327165ad4884e1f90e4",
      [
-      "worklets/idlharness.worker.html",
-      {}
+      "worklets/idlharness.https.any.html",
+      {
+       "script_metadata": [
+        [
+         "script",
+         "/resources/WebIDLParser.js"
+        ],
+        [
+         "script",
+         "/resources/idlharness.js"
+        ]
+       ]
+      }
+     ],
+     [
+      "worklets/idlharness.https.any.worker.html",
+      {
+       "script_metadata": [
+        [
+         "script",
+         "/resources/WebIDLParser.js"
+        ],
+        [
+         "script",
+         "/resources/idlharness.js"
+        ]
+       ]
+      }
      ]
     ],
     "layout-worklet-credentials.https.html": [
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini
deleted file mode 100644
index baa9f1a7541..00000000000
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-005.html]
-  [Miss clipped float]
-    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 19355147aad..d4f69d0abfb 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -312,18 +312,27 @@
   [<iframe>: separate response Content-Type: text/plain */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html;x=" text/plain]
-    expected: FAIL
-
-  [<iframe>: separate response Content-Type: text/html;" text/plain]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
   [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
     expected: FAIL
 
+  [<iframe>: combined response Content-Type: text/html;" text/plain]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: */* text/html]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;x=" text/plain]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+    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 8d0261f22a0..b2ffc8abf78 100644
--- a/tests/wpt/metadata/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
@@ -56,6 +56,6 @@
   [separate text/javascript x/x]
     expected: FAIL
 
-  [separate text/javascript; charset=windows-1252 text/javascript]
+  [separate text/javascript error]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/fetch/h1-parsing/status-code.window.js.ini b/tests/wpt/metadata/fetch/h1-parsing/status-code.window.js.ini
new file mode 100644
index 00000000000..90f03418df6
--- /dev/null
+++ b/tests/wpt/metadata/fetch/h1-parsing/status-code.window.js.ini
@@ -0,0 +1,22 @@
+[status-code.window.html]
+  [HTTP/1.1 999 DOES IT MATTER ]
+    expected: FAIL
+
+  [HTTP/1.1 077 77 ]
+    expected: FAIL
+
+  [HTTP/1.1 200 ]
+    expected: FAIL
+
+  [HTTP/1.1 1 OK ]
+    expected: FAIL
+
+  [HTTP/1.1 099 HELLO ]
+    expected: FAIL
+
+  [HTTP/1.1 99 NOT OK ]
+    expected: FAIL
+
+  [HTTP/1.1 0 OK ]
+    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-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
similarity index 71%
rename from tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
rename to tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
index 51f8272a6de..dc2e45516de 100644
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_3.html]
+[traverse_the_history_5.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini b/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
deleted file mode 100644
index 735a9a75a2a..00000000000
--- a/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[cross-origin-objects-on-new-window.html]
-  expected: TIMEOUT
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_nonescaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 963d4cd20ef..9df1ac56f2a 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
@@ -1,6 +1,6 @@
 [iframe_sandbox_popups_nonescaping-1.html]
   type: testharness
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/forms/textfieldselection/select-event.html.ini b/tests/wpt/metadata/html/semantics/forms/textfieldselection/select-event.html.ini
index 7e0021a4d8f..4a713856a76 100644
--- a/tests/wpt/metadata/html/semantics/forms/textfieldselection/select-event.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/textfieldselection/select-event.html.ini
@@ -1,19 +1,10 @@
 [select-event.html]
-  [input type search: setRangeText() a second time (must not fire select)]
-    expected: FAIL
-
   [input type text: selectionEnd a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: setRangeText() a second time (must not fire select)]
-    expected: FAIL
-
   [input type password: select() a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: selectionStart out of range a second time (must not fire select)]
-    expected: FAIL
-
   [input type search: selectionEnd a second time (must not fire select)]
     expected: FAIL
 
@@ -26,36 +17,57 @@
   [input type password: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: setSelectionRange out of range a second time (must not fire select)]
-    expected: FAIL
-
-  [input type tel: selectionEnd out of range a second time (must not fire select)]
-    expected: FAIL
-
   [textarea: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type url: selectionEnd a second time (must not fire select)]
-    expected: FAIL
-
-  [input type password: selectionEnd out of range a second time (must not fire select)]
-    expected: FAIL
-
   [textarea: setSelectionRange() a second time (must not fire select)]
     expected: FAIL
 
-  [input type tel: setSelectionRange() a second time (must not fire select)]
-    expected: FAIL
-
   [input type url: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
   [input type text: selectionDirection a second time (must not fire select)]
     expected: FAIL
 
-  [input type text: selectionStart out of range a second time (must not fire select)]
-    expected: FAIL
-
   [input type search: selectionStart a second time (must not fire select)]
     expected: FAIL
 
+  [textarea: selectionEnd a second time (must not fire select)]
+    expected: FAIL
+
+  [input type tel: setRangeText() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type url: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: setSelectionRange out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: setSelectionRange out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: setSelectionRange() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: selectionStart out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type text: selectionEnd out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type password: setRangeText() a second time (must not fire select)]
+    expected: FAIL
+
+  [input type search: selectionDirection a second time (must not fire select)]
+    expected: FAIL
+
+  [textarea: selectionStart out of range a second time (must not fire select)]
+    expected: FAIL
+
+  [input type tel: selectionStart a second time (must not fire select)]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini
new file mode 100644
index 00000000000..59a54fe88e4
--- /dev/null
+++ b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html.ini
@@ -0,0 +1,4 @@
+[module-delayed.html]
+  [async document.write in a module]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
deleted file mode 100644
index fca4d908c89..00000000000
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[module-static-import-delayed.html]
-  [document.write in an imported module]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webdriver/tests/idlharness.window.js.ini b/tests/wpt/metadata/webdriver/tests/idlharness.window.js.ini
new file mode 100644
index 00000000000..f89cd1a148d
--- /dev/null
+++ b/tests/wpt/metadata/webdriver/tests/idlharness.window.js.ini
@@ -0,0 +1,7 @@
+[idlharness.window.html]
+  [Navigator interface: navigator must inherit property "webdriver" with the proper type]
+    expected: FAIL
+
+  [Navigator interface: attribute webdriver]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/webmessaging/without-ports/017.html.ini b/tests/wpt/metadata/webmessaging/without-ports/017.html.ini
deleted file mode 100644
index 064cf47545b..00000000000
--- a/tests/wpt/metadata/webmessaging/without-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/web-platform-tests/.azure-pipelines.yml b/tests/wpt/web-platform-tests/.azure-pipelines.yml
index 1c9883ccdec..337d7e326ac 100644
--- a/tests/wpt/web-platform-tests/.azure-pipelines.yml
+++ b/tests/wpt/web-platform-tests/.azure-pipelines.yml
@@ -117,24 +117,6 @@ jobs:
     displayName: 'Run tests (Safari Technology Preview)'
   - template: tools/ci/azure/publish_logs.yml
 
-- job: tools_unittest_mac
-  displayName: 'tools/ unittests: macOS'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.tools_unittest']
-  pool:
-    vmImage: 'macOS-10.15'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  - template: tools/ci/azure/checkout.yml
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/
-      toxenv: py27
-
 - job: tools_unittest_mac_py36
   displayName: 'tools/ unittests: macOS + Python 3.6'
   dependsOn: decision
@@ -167,24 +149,6 @@ jobs:
       directory: tools/
       toxenv: py38
 
-- job: wptrunner_unittest_mac
-  displayName: 'tools/wptrunner/ unittests: macOS'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.wptrunner_unittest']
-  pool:
-    vmImage: 'macOS-10.15'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  - template: tools/ci/azure/checkout.yml
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/wptrunner/
-      toxenv: py27
-
 - job: wptrunner_unittest_mac_py36
   displayName: 'tools/wptrunner/ unittests: macOS + Python 3.6'
   dependsOn: decision
@@ -217,32 +181,6 @@ jobs:
       directory: tools/wptrunner/
       toxenv: py38
 
-- job: wpt_integration_mac
-  displayName: 'tools/wpt/ tests: macOS'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.wpt_integration']
-  pool:
-    vmImage: 'macOS-10.15'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  # full checkout required
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  - template: tools/ci/azure/install_chrome.yml
-  - template: tools/ci/azure/install_firefox.yml
-  - template: tools/ci/azure/update_hosts.yml
-    parameters:
-      pyflag: --py2
-  - template: tools/ci/azure/update_manifest.yml
-    parameters:
-      pyflag: --py2
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/wpt/
-      toxenv: py27
-
 - job: wpt_integration_mac_py36
   displayName: 'tools/wpt/ tests: macOS + Python 3.6'
   dependsOn: decision
@@ -283,24 +221,6 @@ jobs:
       directory: tools/wpt/
       toxenv: py38
 
-- job: tools_unittest_win
-  displayName: 'tools/ unittests: Windows'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.tools_unittest']
-  pool:
-    vmImage: 'windows-2019'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  - template: tools/ci/azure/checkout.yml
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/
-      toxenv: py27
-
 - job: tools_unittest_win_py36
   displayName: 'tools/ unittests: Windows + Python 3.6'
   dependsOn: decision
@@ -337,24 +257,6 @@ jobs:
       directory: tools/
       toxenv: py38
 
-- job: wptrunner_unittest_win
-  displayName: 'tools/wptrunner/ unittests: Windows'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.wptrunner_unittest']
-  pool:
-    vmImage: 'windows-2019'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  - template: tools/ci/azure/checkout.yml
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/wptrunner/
-      toxenv: py27
-
 - job: wptrunner_unittest_win_py36
   displayName: 'tools/wptrunner/ unittests: Windows + Python 3.6'
   dependsOn: decision
@@ -389,34 +291,6 @@ jobs:
       directory: tools/wptrunner/
       toxenv: py38
 
-- job: wpt_integration_win
-  displayName: 'tools/wpt/ tests: Windows'
-  dependsOn: decision
-  condition: dependencies.decision.outputs['test_jobs.wpt_integration']
-  pool:
-    vmImage: 'windows-2019'
-  variables:
-    HYPOTHESIS_PROFILE: ci
-  steps:
-  # full checkout required
-  - task: UsePythonVersion@0
-    inputs:
-      versionSpec: '2.7.x'
-  # currently just using the outdated Chrome/Firefox on the VM rather than
-  # figuring out how to install Chrome Dev channel on Windows
-  # - template: tools/ci/azure/install_chrome.yml
-  # - template: tools/ci/azure/install_firefox.yml
-  - template: tools/ci/azure/update_hosts.yml
-    parameters:
-      pyflag: --py2
-  - template: tools/ci/azure/update_manifest.yml
-    parameters:
-      pyflag: --py2
-  - template: tools/ci/azure/tox_pytest.yml
-    parameters:
-      directory: tools/wpt/
-      toxenv: py27
-
 - job: wpt_integration_win_py36
   displayName: 'tools/wpt/ tests: Windows + Python 3.6'
   dependsOn: decision
diff --git a/tests/wpt/web-platform-tests/clipboard-apis/async-idlharness.https.html b/tests/wpt/web-platform-tests/clipboard-apis/async-idlharness.https.html
deleted file mode 100644
index a1a51c98690..00000000000
--- a/tests/wpt/web-platform-tests/clipboard-apis/async-idlharness.https.html
+++ /dev/null
@@ -1,42 +0,0 @@
-<!doctype html>
-<meta charset=utf-8>
-<title>Clipboard IDL test</title>
-<meta name="timeout" content="long">
-<link rel='help' href='https://w3c.github.io/clipboard-apis/#async-clipboard-api'>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resources/WebIDLParser.js"></script>
-<script src="/resources/idlharness.js"></script>
-<script>
-'use strict';
-
-function doTest(idl, dom, html) {
-  const idl_array = new IdlArray();
-  idl_array.add_untested_idls('interface Navigator {};');
-  idl_array.add_untested_idls('interface EventTarget {};');
-  idl_array.add_untested_idls('dictionary PermissionDescriptor {};');
-  idl_array.add_untested_idls(dom, { only: ['Event', 'EventInit'] });
-  idl_array.add_untested_idls(html, { only: ['DataTransfer', 'DataTransferItemList'] });
-  idl_array.add_idls(idl);
-  idl_array.add_objects({
-    Navigator: ['navigator'],
-    Clipboard: ['navigator.clipboard'],
-    ClipboardEvent: ['new ClipboardEvent("x")'],
-  });
-  idl_array.test();
-};
-
-function fetchText(url) {
-  return fetch(url).then(response => response.text());
-}
-
-promise_test(() => {
-  return Promise.all(
-    [
-      '/interfaces/clipboard-apis.idl',
-      '/interfaces/dom.idl',
-      '/interfaces/html.idl',
-    ].map(fetchText))
-    .then(([idl, dom, html]) => doTest(idl, dom, html));
-}, 'Test driver');
-</script>
diff --git a/tests/wpt/web-platform-tests/clipboard-apis/idlharness.https.window.js b/tests/wpt/web-platform-tests/clipboard-apis/idlharness.https.window.js
new file mode 100644
index 00000000000..c22ee245442
--- /dev/null
+++ b/tests/wpt/web-platform-tests/clipboard-apis/idlharness.https.window.js
@@ -0,0 +1,17 @@
+// META: timeout=long
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+'use strict';
+
+idl_test(
+  ['clipboard-apis'],
+  ['dom', 'html', 'permissions'],
+  idl_array => {
+    idl_array.add_objects({
+      Navigator: ['navigator'],
+      Clipboard: ['navigator.clipboard'],
+      ClipboardEvent: ['new ClipboardEvent("x")'],
+    });
+  }
+);
diff --git a/tests/wpt/web-platform-tests/cookies/cookie-enabled-noncookie-frame.html b/tests/wpt/web-platform-tests/cookies/cookie-enabled-noncookie-frame.html
index 539d715ebd5..2dbbc0bbdc5 100644
--- a/tests/wpt/web-platform-tests/cookies/cookie-enabled-noncookie-frame.html
+++ b/tests/wpt/web-platform-tests/cookies/cookie-enabled-noncookie-frame.html
@@ -6,16 +6,15 @@
 <body>
   <script>
     var t = async_test("navigator.cookieEnabled behavior on frames without cookie access");
-    window.onmessage = function(ev) {
+    window.onmessage = t.step_func_done(ev => {
       // Surprisingly, the legacy behavior here is to return true; this actually
       // does match the spec definition since false is supposed to be returned
       // when a document.cookie write is ignored --- and here it would throw
       // a security exception, not be ignored.
-      assert_equals(ev.data, true);
-      t.done();
-    }
+      assert_true(ev.data);
+    });
 
-    t.step(function() {
+    t.step(() => {
       var iframe = document.createElement("iframe");
       iframe.sandbox = "allow-scripts";
       iframe.srcdoc = "<scr" + "ipt>" +
diff --git a/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001-ref.html b/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001-ref.html
new file mode 100644
index 00000000000..2f40b6c49fd
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001-ref.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Flexbox Reference: display:table flex items with percent-width cells and content keywords for used flex-basis</title>
+<link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+<style>
+  .container {
+    display: block;
+    width: 200px;
+    border: 1px solid black;
+  }
+  table { width: max-content; }
+  td {
+    background-color: cyan;
+    width: 100%;
+    border: 1px solid gray;
+  }
+
+</style>
+<body>
+  <div class="container">
+    <table><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table><tr><td>1</td><td>2</td></tr></table>
+  </div>
+</body>
diff --git a/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001.html b/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001.html
new file mode 100644
index 00000000000..b578b233405
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-flexbox/table-as-item-percent-width-cell-001.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Flexbox Test: display:table flex items with percent-width cells and content keywords for used flex-basis</title>
+<link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#valdef-flex-basis-content">
+<link rel="match" href="table-as-item-percent-width-cell-001-ref.html">
+<meta name="assert" content="If a table as a flex item has used 'flex-basis:content' (or another content-based keyword), and default flex factors, and plenty of space, then it should be sized similarly to a table with 'width:max-content' in a block formatting context.">
+<style>
+  .container {
+    display: flex;
+    width: 200px;
+    border: 1px solid black;
+  }
+  td {
+    background-color: cyan;
+    width: 100%;
+    border: 1px solid gray;
+  }
+
+</style>
+<body>
+  <div class="container">
+    <!-- The used value of flex-basis is 'content' here, due to the flex-basis
+         and the main-size property both having the value 'auto'. -->
+    <table><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table style="flex-basis: content"><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table style="flex-basis: min-content"><tr><td>1</td><td>2</td></tr></table>
+  </div>
+  <div class="container">
+    <table style="flex-basis: max-content"><tr><td>1</td><td>2</td></tr></table>
+  </div>
+</body>
diff --git a/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006-ref.html b/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006-ref.html
new file mode 100644
index 00000000000..06e92eb8395
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006-ref.html
@@ -0,0 +1,90 @@
+<!DOCTYPE HTML>
+<title>CSS Test Reference: breaking of a multicolumn</title>
+<meta charset="utf-8">
+<link rel="author" title="L. David Baron" href="https://dbaron.org/">
+<link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
+<link rel="author" title="Mozilla" href="https://mozilla.org/">
+<style>
+
+.outer {
+  height: 100px;
+  width: 800px;
+  background: rgba(0, 0, 255, 0.3);
+  position: relative;
+}
+
+.blueborders {
+  position: absolute;
+  top: 0;
+  left: 194px; /* 188px first column + (16px gap - 4px rule) / 2 */
+  width: 200px; /* 188px second column + (16px gap - 4px rule) */
+  height: 100px;
+  border-left: blue solid 4px;
+}
+
+.innerbg {
+  height: 100px;
+  width: 188px;
+  background: rgba(255, 0, 255, 0.3);
+  position: absolute;
+  top: 0;
+}
+
+.inner {
+  height: 100px;
+  width: 86px;
+  font: 16px/1.25 sans-serif;
+  position: absolute;
+  top: 0;
+}
+
+.lefthalf {
+  border-right: 2px solid fuchsia;
+  padding-right: 7px;
+}
+
+.righthalf {
+  padding-left: 7px;
+}
+
+.border-bottom {
+  height: 20px;
+  width: 188px;
+  background: green;
+  position: absolute;
+  top: 80px;
+}
+
+</style>
+
+<div class="outer">
+  <div class="blueborders"></div>
+  <div class="innerbg" style="left: 0"></div>
+  <div class="inner lefthalf" style="left: 0">
+    AAAAA<br>
+    BBBBB<br>
+    CCCCC<br>
+    DDDDD<br>
+    EEEEE
+  </div>
+  <div class="inner righthalf" style="left: 95px">
+    FFFFF<br>
+    GGGGG<br>
+    HHHHH<br>
+    IIIII<br>
+    JJJJJ
+  </div>
+  <div class="innerbg" style="left: 204px"></div>
+  <div class="inner lefthalf" style="left: 204px">
+    KKKKK<br>
+    LLLLL<br>
+    MMMMM<br>
+    NNNNN
+  </div>
+  <div class="inner righthalf" style="left: 299px">
+    OOOOO<br>
+    PPPPP<br>
+    QQQQQ<br>
+  </div>
+  <div class="border-bottom" style="left: 204px"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006.html b/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006.html
new file mode 100644
index 00000000000..7efeee80251
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-multicol/multicol-breaking-006.html
@@ -0,0 +1,56 @@
+<!DOCTYPE HTML>
+<title>CSS Test: breaking of a multicolumn</title>
+<meta charset="utf-8">
+<link rel="author" title="L. David Baron" href="https://dbaron.org/">
+<link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
+<link rel="author" title="Mozilla" href="https://mozilla.org/">
+<link rel="help" href="https://drafts.csswg.org/css-multicol/#column-gaps-and-rules">
+<link rel="help" href="https://drafts.csswg.org/css-multicol/#cf">
+<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/2309">
+<link rel="match" href="multicol-breaking-006-ref.html">
+<style>
+
+.outer {
+  height: 100px;
+  column-fill: auto;
+  width: 800px;
+  column-count: 4;
+  column-rule: 4px solid blue;
+  column-gap: 16px;
+  background: rgba(0, 0, 255, 0.3);
+}
+
+.inner {
+  column-count: 2;
+  column-rule: 2px solid fuchsia;
+  column-gap: 16px;
+  background: rgba(255, 0, 255, 0.3);
+  font: 16px/1.25 sans-serif;
+  border-bottom: 20px solid green;
+}
+
+</style>
+
+<!-- This test is adapted from multicol-breaking-001.html.
+     The inner column is changed to have "height:auto" and border-bottom. -->
+<div class="outer">
+  <div class="inner" style="height: auto">
+    AAAAA<br>
+    BBBBB<br>
+    CCCCC<br>
+    DDDDD<br>
+    EEEEE<br>
+    FFFFF<br>
+    GGGGG<br>
+    HHHHH<br>
+    IIIII<br>
+    JJJJJ<br>
+    KKKKK<br>
+    LLLLL<br>
+    MMMMM<br>
+    NNNNN<br>
+    OOOOO<br>
+    PPPPP<br>
+    QQQQQ
+  </div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root-ref.html b/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root-ref.html
new file mode 100644
index 00000000000..a5b2de4f00f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root-ref.html
@@ -0,0 +1,8 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test: non-opaque scrollbar-color should work on the root</title>
+<style>
+:root {
+  background-color: black;
+}
+</style>
diff --git a/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root.html b/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root.html
new file mode 100644
index 00000000000..fcab71127d3
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-scrollbars/transparent-on-root.html
@@ -0,0 +1,14 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test: non-opaque scrollbar-color should work on the root</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-scrollbars-1/#scrollbar-color-properties">
+<link rel="match" href="transparent-on-root-ref.html">
+<style>
+:root {
+  overflow: scroll;
+  scrollbar-color: transparent transparent;
+  background-color: black;
+}
+</style>
diff --git a/tests/wpt/web-platform-tests/docs/running-tests/from-local-system.md b/tests/wpt/web-platform-tests/docs/running-tests/from-local-system.md
index f5cfa36915d..53f6a1fb98d 100644
--- a/tests/wpt/web-platform-tests/docs/running-tests/from-local-system.md
+++ b/tests/wpt/web-platform-tests/docs/running-tests/from-local-system.md
@@ -7,8 +7,7 @@ The tests are designed to be run from your local computer.
 Running the tests requires `python`, `pip` and `virtualenv`, as well as updating
 the system `hosts` file.
 
-Python 3 is supported and preferred, but for now it is still possible to use
-Python 2.7 if necessary.
+WPT requires Python 3.6 or higher.
 
 The required setup is different depending on your operating system.
 
@@ -45,10 +44,10 @@ See also [additional setup required to run Safari](safari.md).
 
 ### Windows Setup
 
-Download and install [Python 2.7](https://www.python.org/downloads). The
+Download and install [Python 3](https://www.python.org/downloads). The
 installer includes `pip` by default.
 
-Add `C:\Python27` and `C:\Python27\Scripts` to your `%Path%`
+Add `C:\Python39` and `C:\Python39\Scripts` to your `%Path%`
 [environment variable](http://www.computerhope.com/issues/ch000549.htm).
 
 Finally, install `virtualenv`:
diff --git a/tests/wpt/web-platform-tests/docs/writing-tests/h2tests.md b/tests/wpt/web-platform-tests/docs/writing-tests/h2tests.md
index c13295e1fe6..9a429373f56 100644
--- a/tests/wpt/web-platform-tests/docs/writing-tests/h2tests.md
+++ b/tests/wpt/web-platform-tests/docs/writing-tests/h2tests.md
@@ -1,7 +1,7 @@
 # Writing H2 Tests
 
-> <b>Important:</b> The HTTP/2.0 server requires you to have Python 2.7.10+
-and OpenSSL 1.0.2+. This is because HTTP/2.0 is negotiated using the
+> <b>Important:</b> The HTTP/2.0 server requires you to have
+OpenSSL 1.0.2+. This is because HTTP/2.0 is negotiated using the
 [TLS ALPN](https://tools.ietf.org/html/rfc7301) extension, which is only supported in [OpenSSL 1.0.2](https://www.openssl.org/news/openssl-1.0.2-notes.html) and up.
 
 These instructions assume you are already familiar with the testing
@@ -153,4 +153,4 @@ the HEADER and CONTINUATION frames are constructed in the same way.
 Ends the stream with the given ID, or the one that request was made on if no ID given.
 
 - <b>Parameters</b>
-    - <b>stream_id</b>: Id of stream to send frame on. Will use the request stream ID if None
\ No newline at end of file
+    - <b>stream_id</b>: Id of stream to send frame on. Will use the request stream ID if None
diff --git a/tests/wpt/web-platform-tests/docs/writing-tests/lint-tool.md b/tests/wpt/web-platform-tests/docs/writing-tests/lint-tool.md
index ba11169e020..95f8b574158 100644
--- a/tests/wpt/web-platform-tests/docs/writing-tests/lint-tool.md
+++ b/tests/wpt/web-platform-tests/docs/writing-tests/lint-tool.md
@@ -61,7 +61,7 @@ TRAILING WHITESPACE:example/*
 
 Similarly, you can also
 use
-[shell-style wildcards](https://docs.python.org/2/library/fnmatch.html) to
+[shell-style wildcards](https://docs.python.org/library/fnmatch.html) to
 express other filename patterns or directory-name patterns.
 
 Finally, to ignore just one line in a file, use the following format:
diff --git a/tests/wpt/web-platform-tests/docs/writing-tests/python-handlers/index.md b/tests/wpt/web-platform-tests/docs/writing-tests/python-handlers/index.md
index e4d396f90a7..96f7edb6160 100644
--- a/tests/wpt/web-platform-tests/docs/writing-tests/python-handlers/index.md
+++ b/tests/wpt/web-platform-tests/docs/writing-tests/python-handlers/index.md
@@ -81,21 +81,6 @@ css/css-align/resources/__init__.py
 This requirement will be removed once we move to Python 3, due to
 [PEP 420](https://www.python.org/dev/peps/pep-0420/).
 
-### Python3 compatibility
-
-Even though Python3 is not fully supported at this point, some work is being
-done to add compatibility for it. This is why you can see in multiple places
-the use of the `six` python module which is meant to provide a set of simple
-utilities that work for both generation of python (see
-[docs](https://six.readthedocs.io/)). The module is vendored in
-tools/third_party/six/six.py.
-
-When an handler is added, it should be at least syntax-compatible with Python3.
-You can check that by running:
-```
-python3 -m py_compile <path/to/handler.py>
-```
-
 ## Example: Dynamic HTTP headers
 
 The following code defines a Python handler that allows the requester to
diff --git a/tests/wpt/web-platform-tests/docs/writing-tests/server-features.md b/tests/wpt/web-platform-tests/docs/writing-tests/server-features.md
index a1ba09132c5..fe3e84836c2 100644
--- a/tests/wpt/web-platform-tests/docs/writing-tests/server-features.md
+++ b/tests/wpt/web-platform-tests/docs/writing-tests/server-features.md
@@ -127,8 +127,8 @@ by default and needs to be run using `./wpt serve --h2` in order to enable it.
 The HTTP/2.0 server supports handlers that work per-frame; these, along with the
 API are documented in [Writing H2 Tests](h2tests).
 
-> <b>Important:</b> The HTTP/2.0 server requires you to have Python 2.7.10+
-and OpenSSL 1.0.2+. This is because HTTP/2.0 is negotiated using the
+> <b>Important:</b> The HTTP/2.0 server requires you to have
+OpenSSL 1.0.2+. This is because HTTP/2.0 is negotiated using the
 [TLS ALPN](https://tools.ietf.org/html/rfc7301) extension, which is only
 supported in
 [OpenSSL 1.0.2](https://www.openssl.org/news/openssl-1.0.2-notes.html) and up.
diff --git a/tests/wpt/web-platform-tests/fetch/h1-parsing/resources/status-code.py b/tests/wpt/web-platform-tests/fetch/h1-parsing/resources/status-code.py
new file mode 100644
index 00000000000..5421893b267
--- /dev/null
+++ b/tests/wpt/web-platform-tests/fetch/h1-parsing/resources/status-code.py
@@ -0,0 +1,6 @@
+def main(request, response):
+    output = b"HTTP/1.1 "
+    output += request.GET.first(b"input")
+    output += b"\nheader-parsing: is sad\n"
+    response.writer.write(output)
+    response.close_connection = True
diff --git a/tests/wpt/web-platform-tests/fetch/h1-parsing/status-code.window.js b/tests/wpt/web-platform-tests/fetch/h1-parsing/status-code.window.js
new file mode 100644
index 00000000000..5776cf4050f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/fetch/h1-parsing/status-code.window.js
@@ -0,0 +1,98 @@
+[
+  {
+    input: "",
+    expected: null
+  },
+  {
+    input: "BLAH",
+    expected: null
+  },
+  {
+    input: "0 OK",
+    expected: {
+      status: 0,
+      statusText: "OK"
+    }
+  },
+  {
+    input: "1 OK",
+    expected: {
+      status: 1,
+      statusText: "OK"
+    }
+  },
+  {
+    input: "99 NOT OK",
+    expected: {
+      status: 99,
+      statusText: "NOT OK"
+    }
+  },
+  {
+    input: "077 77",
+    expected: {
+      status: 77,
+      statusText: "77"
+    }
+  },
+  {
+    input: "099 HELLO",
+    expected: {
+      status: 99,
+      statusText: "HELLO"
+    }
+  },
+  {
+    input: "200",
+    expected: {
+      status: 200,
+      statusText: ""
+    }
+  },
+  {
+    input: "999 DOES IT MATTER",
+    expected: {
+      status: 999,
+      statusText: "DOES IT MATTER"
+    }
+  },
+  {
+    input: "1000 BOO",
+    expected: null
+  },
+  {
+    input: "0200 BOO",
+    expected: null
+  },
+  {
+    input: "65736 NOT 200 OR SOME SUCH",
+    expected: null
+  },
+  {
+    input: "131072 HI",
+    expected: null
+  },
+  {
+    input: "-200 TEST",
+    expected: null
+  },
+  {
+    input: "0xA",
+    expected: null
+  },
+  {
+    input: "C8",
+    expected: null
+  }
+].forEach(({ description, input, expected }) => {
+  promise_test(async t => {
+    if (expected !== null) {
+      const response = await fetch("resources/status-code.py?input=" + input);
+      assert_equals(response.status, expected.status);
+      assert_equals(response.statusText, expected.statusText);
+      assert_equals(response.headers.get("header-parsing"), "is sad");
+    } else {
+      await promise_rejects_js(t, TypeError, fetch("resources/status-code.py?input=" + input));
+    }
+  }, `HTTP/1.1 ${input} ${expected === null ? "(network error)" : ""}`);
+});
diff --git a/tests/wpt/web-platform-tests/layout-instability/transform-above-filter-dynamic.html b/tests/wpt/web-platform-tests/layout-instability/transform-above-filter-dynamic.html
new file mode 100644
index 00000000000..1d7ed51a916
--- /dev/null
+++ b/tests/wpt/web-platform-tests/layout-instability/transform-above-filter-dynamic.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<title>Layout Instability: addition of scale transform above filter</title>
+<link rel="help" href="https://wicg.github.io/layout-instability/" />
+<div id=target style="width: 581px">
+    <div id=moved style="filter: saturate(1.1); width: 300px; height:300px; background: lightblue">
+</div>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/util.js"></script>
+<script>
+promise_test(async () => {
+  const watcher = new ScoreWatcher;
+  // Wait for the initial render to complete.
+  await waitForAnimationFrames(2);
+
+  target.style.transform = "scale(1.1)";
+  await waitForAnimationFrames(1);
+
+  assert_equals(watcher.score, 0);
+}, 'addition of scale transform above filter');
+
+</script>
diff --git a/tests/wpt/web-platform-tests/loading/preloader-link-media.tentative.html b/tests/wpt/web-platform-tests/loading/preloader-link-media.tentative.html
new file mode 100644
index 00000000000..0e58d8b6c89
--- /dev/null
+++ b/tests/wpt/web-platform-tests/loading/preloader-link-media.tentative.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/dummy.js?pipe=trickle(d1)"></script>
+<link rel="stylesheet" media="print" href="resources/dummy.css?print">
+<link rel="stylesheet" href="resources/dummy.css?non-print">
+<script>
+  let t = async_test("Non-matching link media is not preloaded");
+  window.addEventListener("load", t.step_func_done(function() {
+    let entries = performance.getEntriesByType('resource');
+    let found_print = null;
+    let found_non_print = null;
+    for (let entry of entries) {
+      if (entry.name.includes("?print")) {
+        assert_equals(found_print, null);
+        found_print = entry.startTime;
+      }
+      if (entry.name.includes("?non-print")) {
+        assert_equals(found_non_print, null);
+        found_non_print = entry.startTime;
+      }
+    }
+    assert_not_equals(found_print, null, "Should've loaded print sheet");
+    assert_not_equals(found_non_print, null, "Should've loaded non-print sheet");
+    // We can assert_greater_than (rather than greater_than_equal) because if
+    // the non-print sheet has been preloaded but the print one hasn't, we have
+    // the trickle mechanism to try to guarantee that enough time has passed
+    // between one load and the next.
+    assert_greater_than(found_print, found_non_print, "Non-print sheet should've started loading before print sheet")
+  }));
+</script>
+
diff --git a/tests/wpt/web-platform-tests/pointerevents/pointerevent_capture_suppressing_mouse.html b/tests/wpt/web-platform-tests/pointerevents/pointerevent_capture_suppressing_mouse.html
index 080ca1520d9..b621dcb49a9 100644
--- a/tests/wpt/web-platform-tests/pointerevents/pointerevent_capture_suppressing_mouse.html
+++ b/tests/wpt/web-platform-tests/pointerevents/pointerevent_capture_suppressing_mouse.html
@@ -205,13 +205,13 @@
                     .pointerMove(0, 0, {origin: target1})
                     .pointerMove(0, 0, {origin: btnCapture})
                     .pointerDown()
-                    .pointerMove(0, 0, {origin: btnCapture})
+                    .pointerMove(1, 1, {origin: btnCapture})
                     .pointerMove(10, 0, {origin: btnCapture})
                     .pointerMove(0, 0, {origin: target1})
                     .pointerMove(0, 0, {origin: target0})
                     .pointerMove(0, 0, {origin: target1})
                     .pointerUp()
-                    .pointerMove(0, 0, {origin: target1})
+                    .pointerMove(1, 1, {origin: target1})
                     .send();
             }
         </script>
diff --git a/tests/wpt/web-platform-tests/preload/link-header-preload.html b/tests/wpt/web-platform-tests/preload/link-header-preload.html
index b5932a1b0aa..8ad528d0e7c 100644
--- a/tests/wpt/web-platform-tests/preload/link-header-preload.html
+++ b/tests/wpt/web-platform-tests/preload/link-header-preload.html
@@ -1,5 +1,12 @@
 <!DOCTYPE html>
 <title>Makes sure that Link headers preload resources</title>
+<!--
+  This and the line below ensure that the trailing crossorigin in the link
+  header is honored, otherwise we'd load this resource twice and the test would
+  fail.
+-->
+<link rel="preload" as="style" crossorigin href="resources/dummy.css?link-header-crossorigin-preload2">
+<link rel="stylesheet" crossorigin href="resources/dummy.css?link-header-crossorigin-preload2">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/preload/resources/preload_helper.js"></script>
@@ -12,7 +19,9 @@
     function check_finished() {
         if (numberOfResourceTimingEntries("resources/square.png?link-header-preload") == 1 &&
             numberOfResourceTimingEntries("resources/dummy.js?link-header-preload") == 1 &&
-            numberOfResourceTimingEntries("resources/dummy.css?link-header-preload") == 1) {
+            numberOfResourceTimingEntries("resources/dummy.css?link-header-preload") == 1 &&
+            numberOfResourceTimingEntries("resources/dummy.css?link-header-crossorigin-preload1") == 1 &&
+            numberOfResourceTimingEntries("resources/dummy.css?link-header-crossorigin-preload2") == 1) {
             done();
         }
         iterations++;
@@ -21,6 +30,8 @@
             verifyNumberOfResourceTimingEntries("resources/square.png?link-header-preload", 1);
             verifyNumberOfResourceTimingEntries("resources/dummy.js?link-header-preload", 1);
             verifyNumberOfResourceTimingEntries("resources/dummy.css?link-header-preload", 1);
+            verifyNumberOfResourceTimingEntries("resources/dummy.css?link-header-crossorigin-preload1", 1);
+            verifyNumberOfResourceTimingEntries("resources/dummy.css?link-header-crossorigin-preload2", 1);
             done();
         } else {
             step_timeout(check_finished, 500);
diff --git a/tests/wpt/web-platform-tests/preload/link-header-preload.html.headers b/tests/wpt/web-platform-tests/preload/link-header-preload.html.headers
index 293598ee669..83758fb9cdc 100644
--- a/tests/wpt/web-platform-tests/preload/link-header-preload.html.headers
+++ b/tests/wpt/web-platform-tests/preload/link-header-preload.html.headers
@@ -1,4 +1,6 @@
 Link: </preload/resources/dummy.js?link-header-preload>;rel=preload;as=script
 Link: </preload/resources/dummy.css?link-header-preload>;rel=preload;as=style
 Link: </preload/resources/square.png?link-header-preload>;rel=preload;as=image
+Link: </preload/resources/dummy.css?link-header-crossorigin-preload1>;rel=preload;as=style;crossorigin
+Link: </preload/resources/dummy.css?link-header-crossorigin-preload2>;rel=preload;as=style;crossorigin
 
diff --git a/tests/wpt/web-platform-tests/resources/chromium/generic_sensor_mocks.js b/tests/wpt/web-platform-tests/resources/chromium/generic_sensor_mocks.js
index 85891c6ef12..56438824518 100644
--- a/tests/wpt/web-platform-tests/resources/chromium/generic_sensor_mocks.js
+++ b/tests/wpt/web-platform-tests/resources/chromium/generic_sensor_mocks.js
@@ -215,6 +215,8 @@ var GenericSensorTest = (() => {
         ['Accelerometer', device.mojom.SensorType.ACCELEROMETER],
         ['LinearAccelerationSensor',
             device.mojom.SensorType.LINEAR_ACCELERATION],
+        ['GravitySensor',
+            device.mojom.SensorType.GRAVITY],
         ['AmbientLightSensor', device.mojom.SensorType.AMBIENT_LIGHT],
         ['Gyroscope', device.mojom.SensorType.GYROSCOPE],
         ['Magnetometer', device.mojom.SensorType.MAGNETOMETER],
diff --git a/tests/wpt/web-platform-tests/resources/idlharness.js b/tests/wpt/web-platform-tests/resources/idlharness.js
index 5a97b273f2b..76131e7c960 100644
--- a/tests/wpt/web-platform-tests/resources/idlharness.js
+++ b/tests/wpt/web-platform-tests/resources/idlharness.js
@@ -3543,8 +3543,6 @@ IdlNamespace.prototype.test = function ()
 function idl_test(srcs, deps, idl_setup_func) {
     return promise_test(function (t) {
         var idl_array = new IdlArray();
-        srcs = (srcs instanceof Array) ? srcs : [srcs] || [];
-        deps = (deps instanceof Array) ? deps : [deps] || [];
         var setup_error = null;
         const validationIgnored = [
             "constructor-member",
diff --git a/tests/wpt/web-platform-tests/tools/ci/azure/update_hosts.yml b/tests/wpt/web-platform-tests/tools/ci/azure/update_hosts.yml
index 64aff7cf46a..63c7e458112 100644
--- a/tests/wpt/web-platform-tests/tools/ci/azure/update_hosts.yml
+++ b/tests/wpt/web-platform-tests/tools/ci/azure/update_hosts.yml
@@ -1,6 +1,3 @@
-parameters:
-  pyflag: --py3
-
 steps:
 - script: ./wpt make-hosts-file | sudo tee -a /etc/hosts
   displayName: 'Update hosts (macOS)'
@@ -8,6 +5,6 @@ steps:
 - powershell: |
     $hostFile = "$env:systemroot\System32\drivers\etc\hosts"
     Copy-Item -Path $hostFile -Destination "$hostFile.back" -Force
-    python wpt ${{ parameters.pyflag }} make-hosts-file | Out-File $env:systemroot\System32\drivers\etc\hosts -Encoding ascii -Append
+    python wpt make-hosts-file | Out-File $env:systemroot\System32\drivers\etc\hosts -Encoding ascii -Append
   displayName: 'Update hosts (Windows)'
   condition: and(succeeded(), eq(variables['Agent.OS'], 'Windows_NT'))
diff --git a/tests/wpt/web-platform-tests/tools/ci/azure/update_manifest.yml b/tests/wpt/web-platform-tests/tools/ci/azure/update_manifest.yml
index e8f28217f1e..453ac2ac3c0 100644
--- a/tests/wpt/web-platform-tests/tools/ci/azure/update_manifest.yml
+++ b/tests/wpt/web-platform-tests/tools/ci/azure/update_manifest.yml
@@ -1,7 +1,4 @@
-parameters:
-  pyflag: --py3
-
 steps:
 # `python wpt` instead of `./wpt` is to make this work on Windows:
-- script: python wpt ${{ parameters.pyflag }} manifest
+- script: python wpt manifest
   displayName: 'Update manifest'
diff --git a/tests/wpt/web-platform-tests/tools/ci/tc/tasks/test.yml b/tests/wpt/web-platform-tests/tools/ci/tc/tasks/test.yml
index b3a39606893..95212e97bf7 100644
--- a/tests/wpt/web-platform-tests/tools/ci/tc/tasks/test.yml
+++ b/tests/wpt/web-platform-tests/tools/ci/tc/tasks/test.yml
@@ -105,11 +105,6 @@ components:
 
   browser-servo: {}
 
-  tox-python2:
-    env:
-      TOXENV: py27
-      PY_COLORS: 0
-
   tox-python3:
     env:
       TOXENV: py36
@@ -402,20 +397,6 @@ tasks:
           - update_built
       command: "./tools/ci/ci_built_diff.sh"
 
-  - tools/ unittests (Python 2):
-      use:
-        - wpt-base
-        - trigger-pr
-        - tox-python2
-      description: >-
-        Unit tests for tools running under Python 2.7, excluding wptrunner
-      command: ./tools/ci/ci_tools_unittest.sh
-      env:
-        HYPOTHESIS_PROFILE: ci
-      schedule-if:
-        run-job:
-          - tools_unittest
-
   - tools/ unittests (Python 3.6):
       description: >-
         Unit tests for tools running under Python 3.6, excluding wptrunner
@@ -447,28 +428,6 @@ tasks:
         run-job:
           - tools_unittest
 
-  - tools/ integration tests (Python 2):
-      description: >-
-        Integration tests for tools running under Python 2.7
-      use:
-        - wpt-base
-        - trigger-pr
-        - tox-python2
-      command: ./tools/ci/ci_tools_integration_test.sh
-      install:
-        - libnss3-tools
-      options:
-        oom-killer: true
-        browser:
-          - firefox
-          - chrome
-        channel: experimental
-        xvfb: true
-        hosts: true
-      schedule-if:
-        run-job:
-          - wpt_integration
-
   - tools/ integration tests (Python 3.6):
       description: >-
         Integration tests for tools running under Python 3.6
@@ -515,23 +474,6 @@ tasks:
         run-job:
           - wpt_integration
 
-  - resources/ tests (Python 2):
-      description: >-
-        Tests for testharness.js and other files in resources/ under Python 2.7
-      use:
-        - wpt-base
-        - trigger-pr
-        - tox-python2
-      command: ./tools/ci/ci_resources_unittest.sh
-      options:
-        browser:
-          - firefox
-        xvfb: true
-        hosts: true
-      schedule-if:
-        run-job:
-          - resources_unittest
-  
   - resources/ tests (Python 3.6):
       description: >-
         Tests for testharness.js and other files in resources/ under Python 3.6
@@ -572,32 +514,6 @@ tasks:
         run-job:
           - resources_unittest
 
-  - infrastructure/ tests:
-      description: >-
-        Smoketests for wptrunner
-      vars:
-        channel: nightly
-      use:
-        - wpt-base
-        - trigger-pr
-        - browser-firefox
-      command: ./tools/ci/ci_wptrunner_infrastructure.sh --py2
-      install:
-        - libnss3-tools
-        - libappindicator1
-        - fonts-liberation
-      options:
-        oom-killer: true
-        browser:
-          - firefox
-          - chrome
-        channel: experimental
-        xvfb: true
-        hosts: false
-      schedule-if:
-        run-job:
-          - wptrunner_infrastructure
-
   - infrastructure/ tests (Python 3):
       description: >-
         Smoketests for wptrunner
diff --git a/tests/wpt/web-platform-tests/tools/ci/tc/tests/test_valid.py b/tests/wpt/web-platform-tests/tools/ci/tc/tests/test_valid.py
index 30fdfdc13d8..9891e1cfc5d 100644
--- a/tests/wpt/web-platform-tests/tools/ci/tc/tests/test_valid.py
+++ b/tests/wpt/web-platform-tests/tools/ci/tc/tests/test_valid.py
@@ -132,17 +132,13 @@ def test_verify_payload():
       'lint']),
     ("pr_event.json", True, {".taskcluster.yml", ".travis.yml", "tools/ci/start.sh"},
      ['lint',
-      'tools/ unittests (Python 2)',
       'tools/ unittests (Python 3.6)',
       'tools/ unittests (Python 3.8)',
-      'tools/ integration tests (Python 2)',
       'tools/ integration tests (Python 3.6)',
       'tools/ integration tests (Python 3.8)',
-      'resources/ tests (Python 2)',
       'resources/ tests (Python 3.6)',
       'resources/ tests (Python 3.8)',
       'download-firefox-nightly',
-      'infrastructure/ tests',
       'infrastructure/ tests (Python 3)',
       'sink-task']),
     # More tests are affected in the actual PR but it shouldn't affect the scheduled tasks
diff --git a/tests/wpt/web-platform-tests/tools/py3-flake8.ini b/tests/wpt/web-platform-tests/tools/py3-flake8.ini
index 14cc1dc6f6a..f8d4776ef66 100644
--- a/tests/wpt/web-platform-tests/tools/py3-flake8.ini
+++ b/tests/wpt/web-platform-tests/tools/py3-flake8.ini
@@ -12,16 +12,16 @@ select = E,W,F,N
 # E402: module level import not at top of file
 # E731: do not assign a lambda expression, use a def
 # W504: line break after binary operator
+# W601: .has_key() is deprecated, use ‘in’
 # W605: invalid escape sequence
 # N801: class names should use CapWords convention
 # N802: function name should be lowercase
 # N806: variable in function should be lowercase
-ignore = E128,E129,E226,E231,E251,E265,E302,E303,E305,E402,E731,W504,W605,N801,N802,N806
+ignore = E128,E129,E226,E231,E251,E265,E302,E303,E305,E402,E731,W504,W601,W605,N801,N802,N806
 exclude =
     .tox,
     pywebsocket,
     third_party,
-    wptrunner,
     wptserve/docs/conf.py,
     wptserve/tests/functional/docroot/invalid.py
 max-line-length = 141
diff --git a/tests/wpt/web-platform-tests/tools/wpt/install.py b/tests/wpt/web-platform-tests/tools/wpt/install.py
index 638065a5301..8ba5c7a8591 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/install.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/install.py
@@ -2,6 +2,8 @@ import argparse
 from . import browser
 
 latest_channels = {
+    'android_weblayer': 'dev',
+    'android_webview': 'dev',
     'firefox': 'nightly',
     'chrome': 'nightly',
     'chrome_android': 'dev',
diff --git a/tests/wpt/web-platform-tests/tools/wpt/run.py b/tests/wpt/web-platform-tests/tools/wpt/run.py
index 3d380eab5cb..68f8e32ca18 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/run.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/run.py
@@ -427,10 +427,12 @@ class ChromeiOS(BrowserSetup):
 class AndroidWeblayer(BrowserSetup):
     name = "android_weblayer"
     browser_cls = browser.AndroidWeblayer
+    experimental_channels = ("dev", "canary")
 
     def setup_kwargs(self, kwargs):
         if kwargs.get("device_serial"):
             self.browser.device_serial = kwargs["device_serial"]
+        browser_channel = kwargs["browser_channel"]
         if kwargs["webdriver_binary"] is None:
             webdriver_binary = None
             if not kwargs["install_webdriver"]:
@@ -443,7 +445,7 @@ class AndroidWeblayer(BrowserSetup):
                     logger.info("Downloading chromedriver")
                     webdriver_binary = self.browser.install_webdriver(
                         dest=self.venv.bin_path,
-                        channel=kwargs["browser_channel"])
+                        channel=browser_channel)
             else:
                 logger.info("Using webdriver binary %s" % webdriver_binary)
 
@@ -451,6 +453,9 @@ class AndroidWeblayer(BrowserSetup):
                 kwargs["webdriver_binary"] = webdriver_binary
             else:
                 raise WptrunError("Unable to locate or install chromedriver binary")
+        if browser_channel in self.experimental_channels:
+            logger.info("Automatically turning on experimental features for WebLayer Dev/Canary")
+            kwargs["binary_args"].append("--enable-experimental-web-platform-features")
 
 
 class AndroidWebview(BrowserSetup):
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_weblayer.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_weblayer.py
index f68312f231b..972e5517b1c 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_weblayer.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_weblayer.py
@@ -1,9 +1,7 @@
-import subprocess
-
-from .base import Browser, ExecutorBrowser, require_arg
+from .base import require_arg
 from .base import get_timeout_multiplier   # noqa: F401
 from .chrome import executor_kwargs as chrome_executor_kwargs
-from ..webdriver_server import ChromeDriverServer
+from .chrome_android import ChromeAndroidBrowserBase
 from ..executors.executorwebdriver import (WebDriverTestharnessExecutor,  # noqa: F401
                                            WebDriverRefTestExecutor)  # noqa: F401
 from ..executors.executorchrome import ChromeDriverWdspecExecutor  # noqa: F401
@@ -74,61 +72,19 @@ def env_options():
     return {"server_host": "127.0.0.1"}
 
 
-#TODO: refactor common elements of WeblayerShell and ChromeAndroidBrowser
-class WeblayerShell(Browser):
+class WeblayerShell(ChromeAndroidBrowserBase):
     """Chrome is backed by chromedriver, which is supplied through
     ``wptrunner.webdriver.ChromeDriverServer``.
     """
 
-    def __init__(self, logger, binary, webdriver_binary="chromedriver",
+    def __init__(self, logger, binary,
+                 webdriver_binary="chromedriver",
+                 remote_queue=None,
                  device_serial=None,
                  webdriver_args=None):
         """Creates a new representation of Chrome.  The `binary` argument gives
         the browser binary to use for testing."""
-        Browser.__init__(self, logger)
+        super(WeblayerShell, self).__init__(logger,
+                webdriver_binary, remote_queue, device_serial, webdriver_args)
         self.binary = binary
-        self.device_serial = device_serial
-        self.server = ChromeDriverServer(self.logger,
-                                         binary=webdriver_binary,
-                                         args=webdriver_args)
-        self.setup_adb_reverse()
-
-    def _adb_run(self, args):
-        cmd = ['adb']
-        if self.device_serial:
-            cmd.extend(['-s', self.device_serial])
-        cmd.extend(args)
-        self.logger.info(' '.join(cmd))
-        subprocess.check_call(cmd)
-
-    def setup_adb_reverse(self):
-        self._adb_run(['wait-for-device'])
-        self._adb_run(['forward', '--remove-all'])
-        self._adb_run(['reverse', '--remove-all'])
-        # "adb reverse" basically forwards network connection from device to
-        # host.
-        for port in _wptserve_ports:
-            self._adb_run(['reverse', 'tcp:%d' % port, 'tcp:%d' % port])
-
-    def start(self, **kwargs):
-        self.server.start(block=False)
-
-    def stop(self, force=False):
-        self.server.stop(force=force)
-
-    def pid(self):
-        return self.server.pid
-
-    def is_alive(self):
-        # TODO(ato): This only indicates the driver is alive,
-        # and doesn't say anything about whether a browser session
-        # is active.
-        return self.server.is_alive()
-
-    def cleanup(self):
-        self.stop()
-        self._adb_run(['forward', '--remove-all'])
-        self._adb_run(['reverse', '--remove-all'])
-
-    def executor_browser(self):
-        return ExecutorBrowser, {"webdriver_url": self.server.url}
+        self.wptserver_ports = _wptserve_ports
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_webview.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_webview.py
index 3cde248b446..918a881b908 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_webview.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/android_webview.py
@@ -1,9 +1,7 @@
-import subprocess
-
-from .base import Browser, ExecutorBrowser, require_arg
+from .base import require_arg
 from .base import get_timeout_multiplier   # noqa: F401
 from .chrome import executor_kwargs as chrome_executor_kwargs
-from ..webdriver_server import ChromeDriverServer
+from .chrome_android import ChromeAndroidBrowserBase
 from ..executors.executorwebdriver import (WebDriverTestharnessExecutor,  # noqa: F401
                                            WebDriverRefTestExecutor)  # noqa: F401
 from ..executors.executorchrome import ChromeDriverWdspecExecutor  # noqa: F401
@@ -73,61 +71,18 @@ def env_options():
     return {"server_host": "127.0.0.1"}
 
 
-#TODO: refactor common elements of SystemWebViewShell and ChromeAndroidBrowser
-class SystemWebViewShell(Browser):
+class SystemWebViewShell(ChromeAndroidBrowserBase):
     """Chrome is backed by chromedriver, which is supplied through
     ``wptrunner.webdriver.ChromeDriverServer``.
     """
 
     def __init__(self, logger, binary, webdriver_binary="chromedriver",
+                 remote_queue=None,
                  device_serial=None,
                  webdriver_args=None):
         """Creates a new representation of Chrome.  The `binary` argument gives
         the browser binary to use for testing."""
-        Browser.__init__(self, logger)
+        super(SystemWebViewShell, self).__init__(logger,
+                webdriver_binary, remote_queue, device_serial, webdriver_args)
         self.binary = binary
-        self.device_serial = device_serial
-        self.server = ChromeDriverServer(self.logger,
-                                         binary=webdriver_binary,
-                                         args=webdriver_args)
-        self.setup_adb_reverse()
-
-    def _adb_run(self, args):
-        cmd = ['adb']
-        if self.device_serial:
-            cmd.extend(['-s', self.device_serial])
-        cmd.extend(args)
-        self.logger.info(' '.join(cmd))
-        subprocess.check_call(cmd)
-
-    def setup_adb_reverse(self):
-        self._adb_run(['wait-for-device'])
-        self._adb_run(['forward', '--remove-all'])
-        self._adb_run(['reverse', '--remove-all'])
-        # "adb reverse" basically forwards network connection from device to
-        # host.
-        for port in _wptserve_ports:
-            self._adb_run(['reverse', 'tcp:%d' % port, 'tcp:%d' % port])
-
-    def start(self, **kwargs):
-        self.server.start(block=False)
-
-    def stop(self, force=False):
-        self.server.stop(force=force)
-
-    def pid(self):
-        return self.server.pid
-
-    def is_alive(self):
-        # TODO(ato): This only indicates the driver is alive,
-        # and doesn't say anything about whether a browser session
-        # is active.
-        return self.server.is_alive()
-
-    def cleanup(self):
-        self.stop()
-        self._adb_run(['forward', '--remove-all'])
-        self._adb_run(['reverse', '--remove-all'])
-
-    def executor_browser(self):
-        return ExecutorBrowser, {"webdriver_url": self.server.url}
+        self.wptserver_ports = _wptserve_ports
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome.py
index d3e27a9c5f6..04ac3726fba 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome.py
@@ -113,7 +113,7 @@ class ChromeBrowser(Browser):
     """
 
     def __init__(self, logger, binary, webdriver_binary="chromedriver",
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         """Creates a new representation of Chrome.  The `binary` argument gives
         the browser binary to use for testing."""
         Browser.__init__(self, logger)
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_android.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_android.py
index d7e3e210121..178183b4028 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_android.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_android.py
@@ -1,3 +1,4 @@
+import mozprocess
 import subprocess
 
 from .base import Browser, ExecutorBrowser, require_arg
@@ -68,21 +69,75 @@ def env_options():
     # allow the use of host-resolver-rules in lieu of modifying /etc/hosts file
     return {"server_host": "127.0.0.1"}
 
+class LogcatRunner(object):
+    def __init__(self, logger, browser, remote_queue):
+        self.logger = logger
+        self.browser = browser
+        self.remote_queue = remote_queue
 
-class ChromeAndroidBrowser(Browser):
-    """Chrome is backed by chromedriver, which is supplied through
-    ``wptrunner.webdriver.ChromeDriverServer``.
-    """
+    def start(self):
+        try:
+            self._run()
+        except KeyboardInterrupt:
+            self.stop()
 
-    def __init__(self, logger, package_name, webdriver_binary="chromedriver",
+    def _run(self):
+        try:
+            # TODO: adb logcat -c fail randomly with message
+            # "failed to clear the 'main' log"
+            self.browser.clear_log()
+        except subprocess.CalledProcessError:
+            self.logger.error("Failed to clear logcat buffer")
+
+        self._cmd = self.browser.logcat_cmd()
+        self._proc = mozprocess.ProcessHandler(
+            self._cmd,
+            processOutputLine=self.on_output,
+            storeOutput=False)
+        self._proc.run()
+
+    def _send_message(self, command, *args):
+        try:
+            self.remote_queue.put((command, args))
+        except AssertionError:
+            self.logger.warning("Error when send to remote queue")
+
+    def stop(self, force=False):
+        if self.is_alive():
+            kill_result = self._proc.kill()
+            if force and kill_result != 0:
+                self._proc.kill(9)
+
+    def is_alive(self):
+        return hasattr(self._proc, "proc") and self._proc.poll() is None
+
+    def on_output(self, line):
+        data = {
+            "process": "LOGCAT",
+            "command": "logcat",
+            "data": line
+        }
+        self._send_message("log", "process_output", data)
+
+class ChromeAndroidBrowserBase(Browser):
+    def __init__(self, logger,
+                 webdriver_binary="chromedriver",
+                 remote_queue = None,
                  device_serial=None, webdriver_args=None):
-        Browser.__init__(self, logger)
-        self.package_name = package_name
+        super(ChromeAndroidBrowserBase, self).__init__(logger)
         self.device_serial = device_serial
+        self.remote_queue = remote_queue
         self.server = ChromeDriverServer(self.logger,
                                          binary=webdriver_binary,
                                          args=webdriver_args)
+        if self.remote_queue is not None:
+            self.logcat_runner = LogcatRunner(self.logger,
+                                          self, self.remote_queue)
+
+    def setup(self):
         self.setup_adb_reverse()
+        if self.remote_queue is not None:
+            self.logcat_runner.start()
 
     def _adb_run(self, args):
         cmd = ['adb']
@@ -92,14 +147,6 @@ class ChromeAndroidBrowser(Browser):
         self.logger.info(' '.join(cmd))
         subprocess.check_call(cmd)
 
-    def setup_adb_reverse(self):
-        self._adb_run(['wait-for-device'])
-        self._adb_run(['forward', '--remove-all'])
-        self._adb_run(['reverse', '--remove-all'])
-        # "adb reverse" forwards network connection from device to host.
-        for port in _wptserve_ports:
-            self._adb_run(['reverse', 'tcp:%d' % port, 'tcp:%d' % port])
-
     def start(self, **kwargs):
         self.server.start(block=False)
 
@@ -119,6 +166,40 @@ class ChromeAndroidBrowser(Browser):
         self.stop()
         self._adb_run(['forward', '--remove-all'])
         self._adb_run(['reverse', '--remove-all'])
+        if self.remote_queue is not None:
+            self.logcat_runner.stop(force=True)
 
     def executor_browser(self):
         return ExecutorBrowser, {"webdriver_url": self.server.url}
+
+    def clear_log(self):
+        self._adb_run(['logcat', '-c'])
+
+    def logcat_cmd(self):
+        cmd = ['adb']
+        if self.device_serial:
+            cmd.extend(['-s', self.device_serial])
+        cmd.extend(['logcat', '*:D'])
+        return cmd
+
+    def setup_adb_reverse(self):
+        self._adb_run(['wait-for-device'])
+        self._adb_run(['forward', '--remove-all'])
+        self._adb_run(['reverse', '--remove-all'])
+        # "adb reverse" forwards network connection from device to host.
+        for port in self.wptserver_ports:
+            self._adb_run(['reverse', 'tcp:%d' % port, 'tcp:%d' % port])
+
+class ChromeAndroidBrowser(ChromeAndroidBrowserBase):
+    """Chrome is backed by chromedriver, which is supplied through
+    ``wptrunner.webdriver.ChromeDriverServer``.
+    """
+
+    def __init__(self, logger, package_name,
+                 webdriver_binary="chromedriver",
+                 remote_queue = None,
+                 device_serial=None, webdriver_args=None):
+        super(ChromeAndroidBrowser, self).__init__(logger,
+                webdriver_binary, remote_queue, device_serial, webdriver_args)
+        self.package_name = package_name
+        self.wptserver_ports = _wptserve_ports
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_ios.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_ios.py
index ecdbc3a1762..f349b19419c 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_ios.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/chrome_ios.py
@@ -51,7 +51,7 @@ class ChromeiOSBrowser(Browser):
 
     init_timeout = 120
 
-    def __init__(self, logger, webdriver_binary, webdriver_args=None):
+    def __init__(self, logger, webdriver_binary, webdriver_args=None, **kwargs):
         """Creates a new representation of Chrome."""
         Browser.__init__(self, logger)
         self.server = CWTChromeDriverServer(self.logger,
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edge.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edge.py
index b908684bbb3..db4795ce5d4 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edge.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edge.py
@@ -68,7 +68,8 @@ class EdgeBrowser(Browser):
     used_ports = set()
     init_timeout = 60
 
-    def __init__(self, logger, webdriver_binary, timeout_multiplier=None, webdriver_args=None):
+    def __init__(self, logger, webdriver_binary,
+            timeout_multiplier=None, webdriver_args=None, **kwargs):
         Browser.__init__(self, logger)
         self.server = EdgeDriverServer(self.logger,
                                        binary=webdriver_binary,
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edgechromium.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edgechromium.py
index 1d45983a11e..c2275bd1687 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edgechromium.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/edgechromium.py
@@ -85,7 +85,7 @@ class EdgeChromiumBrowser(Browser):
     """
 
     def __init__(self, logger, binary, webdriver_binary="msedgedriver",
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         """Creates a new representation of MicrosoftEdge.  The `binary` argument gives
         the browser binary to use for testing."""
         Browser.__init__(self, logger)
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/epiphany.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/epiphany.py
index a3384436a1d..f378170f33d 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/epiphany.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/epiphany.py
@@ -72,6 +72,6 @@ def run_info_extras(**kwargs):
 
 class EpiphanyBrowser(WebKitBrowser):
     def __init__(self, logger, binary=None, webdriver_binary=None,
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         WebKitBrowser.__init__(self, logger, binary, webdriver_binary,
                                webdriver_args)
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/ie.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/ie.py
index 3a86c1b6ccb..5fce29a4770 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/ie.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/ie.py
@@ -43,7 +43,7 @@ def env_options():
 class InternetExplorerBrowser(Browser):
     used_ports = set()
 
-    def __init__(self, logger, webdriver_binary, webdriver_args=None):
+    def __init__(self, logger, webdriver_binary, webdriver_args=None, **kwargs):
         Browser.__init__(self, logger)
         self.server = InternetExplorerDriverServer(self.logger,
                                                    binary=webdriver_binary,
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/opera.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/opera.py
index a34f4195538..80e5a314c83 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/opera.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/opera.py
@@ -71,7 +71,7 @@ class OperaBrowser(Browser):
     """
 
     def __init__(self, logger, binary, webdriver_binary="operadriver",
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         """Creates a new representation of Opera.  The `binary` argument gives
         the browser binary to use for testing."""
         Browser.__init__(self, logger)
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/safari.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/safari.py
index 312d4db9c63..0f62639c635 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/safari.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/safari.py
@@ -58,7 +58,7 @@ class SafariBrowser(Browser):
     ``wptrunner.webdriver.SafariDriverServer``.
     """
 
-    def __init__(self, logger, webdriver_binary, webdriver_args=None):
+    def __init__(self, logger, webdriver_binary, webdriver_args=None, **kwargs):
         """Creates a new representation of Safari.  The `webdriver_binary`
         argument gives the WebDriver binary to use for testing. (The browser
         binary location cannot be specified, as Safari and SafariDriver are
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/sauce.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/sauce.py
index 3497c5c2772..483bf206172 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/sauce.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/sauce.py
@@ -228,7 +228,7 @@ class SauceException(Exception):
 class SauceBrowser(Browser):
     init_timeout = 300
 
-    def __init__(self, logger, sauce_config):
+    def __init__(self, logger, sauce_config, **kwargs):
         Browser.__init__(self, logger)
         self.sauce_config = sauce_config
 
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servo.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servo.py
index a65ed5ead4e..4f934aedfcd 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servo.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servo.py
@@ -71,7 +71,7 @@ def update_properties():
 
 class ServoBrowser(NullBrowser):
     def __init__(self, logger, binary, debug_info=None, binary_args=None,
-                 user_stylesheets=None, ca_certificate_path=None):
+                 user_stylesheets=None, ca_certificate_path=None, **kwargs):
         NullBrowser.__init__(self, logger)
         self.binary = binary
         self.debug_info = debug_info
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servodriver.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servodriver.py
index ed85cbf3b9b..83b9423ba71 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servodriver.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servodriver.py
@@ -77,7 +77,8 @@ class ServoWebDriverBrowser(Browser):
     init_timeout = 300  # Large timeout for cases where we're booting an Android emulator
 
     def __init__(self, logger, binary, debug_info=None, webdriver_host="127.0.0.1",
-                 server_config=None, binary_args=None, user_stylesheets=None, headless=None):
+                 server_config=None, binary_args=None,
+                 user_stylesheets=None, headless=None, **kwargs):
         Browser.__init__(self, logger)
         self.binary = binary
         self.binary_args = binary_args or []
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkit.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkit.py
index 590e472aca9..f83de2996a9 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkit.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkit.py
@@ -82,7 +82,7 @@ class WebKitBrowser(Browser):
     """
 
     def __init__(self, logger, binary, webdriver_binary=None,
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         Browser.__init__(self, logger)
         self.binary = binary
         self.server = WebKitDriverServer(self.logger, binary=webdriver_binary,
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkitgtk_minibrowser.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkitgtk_minibrowser.py
index 5b7a360fb60..6c1001e2d70 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkitgtk_minibrowser.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/webkitgtk_minibrowser.py
@@ -76,6 +76,6 @@ def run_info_extras(**kwargs):
 
 class WebKitGTKMiniBrowser(WebKitBrowser):
     def __init__(self, logger, binary=None, webdriver_binary=None,
-                 webdriver_args=None):
+                 webdriver_args=None, **kwargs):
         WebKitBrowser.__init__(self, logger, binary, webdriver_binary,
                                webdriver_args)
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/formatters/chromium.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/formatters/chromium.py
index 2ff2bd1e083..b6cbb203a31 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/formatters/chromium.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/formatters/chromium.py
@@ -272,5 +272,6 @@ class ChromiumFormatter(base.BaseFormatter):
         return json.dumps(final_result)
 
     def process_output(self, data):
-        if 'command' in data and 'chromedriver' in data['command']:
+        cmd = data.get("command", "")
+        if any(c in cmd for c in ["chromedriver", "logcat"]):
             self.browser_log.append(data['data'])
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/testrunner.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/testrunner.py
index 8dd93418dd8..0c658a158a3 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/testrunner.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/testrunner.py
@@ -361,7 +361,8 @@ class TestRunnerManager(threading.Thread):
         spins."""
         self.recording.set(["testrunner", "startup"])
         self.logger = structuredlog.StructuredLogger(self.suite_name)
-        with self.browser_cls(self.logger, **self.browser_kwargs) as browser:
+        with self.browser_cls(self.logger, remote_queue=self.command_queue,
+                              **self.browser_kwargs) as browser:
             self.browser = BrowserManager(self.logger,
                                           browser,
                                           self.command_queue,
diff --git a/tests/wpt/web-platform-tests/webdriver/tests/idlharness.html b/tests/wpt/web-platform-tests/webdriver/tests/idlharness.html
deleted file mode 100644
index d049d835f2f..00000000000
--- a/tests/wpt/web-platform-tests/webdriver/tests/idlharness.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!doctype html>
-<meta charset=utf-8>
-<link rel="help" href="https://w3c.github.io/webdriver/">
-<script src=/resources/testharness.js></script>
-<script src=/resources/testharnessreport.js></script>
-<script src=/resources/WebIDLParser.js></script>
-<script src=/resources/idlharness.js></script>
-
-<script>
-  "use strict";
-
-  promise_test(async () => {
-    const idl_array = new IdlArray();
-    const idl = await fetch("/interfaces/webdriver.idl").then(r => r.text());
-    const html = await fetch("/interfaces/html.idl").then(r => r.text());
-    idl_array.add_idls(idl);
-    idl_array.add_dependency_idls(html);
-    idl_array.add_objects({
-      Navigator: ["navigator"]
-    });
-    idl_array.test();
-  }, "Test IDL implementation of webdriver API");
-</script>
diff --git a/tests/wpt/web-platform-tests/webdriver/tests/idlharness.window.js b/tests/wpt/web-platform-tests/webdriver/tests/idlharness.window.js
new file mode 100644
index 00000000000..e92e151d898
--- /dev/null
+++ b/tests/wpt/web-platform-tests/webdriver/tests/idlharness.window.js
@@ -0,0 +1,16 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+// https://w3c.github.io/webdriver/
+
+"use strict";
+
+idl_test(
+  ["webdriver"],
+  ["html"],
+  idl_array => {
+    idl_array.add_objects({
+      Navigator: ["navigator"]
+    });
+  }
+);
diff --git a/tests/wpt/web-platform-tests/worklets/idlharness.https.any.js b/tests/wpt/web-platform-tests/worklets/idlharness.https.any.js
new file mode 100644
index 00000000000..2900b381249
--- /dev/null
+++ b/tests/wpt/web-platform-tests/worklets/idlharness.https.any.js
@@ -0,0 +1,11 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+// https://drafts.css-houdini.org/worklets/
+
+'use strict';
+
+idl_test(
+  ['worklets'],
+  []
+);
diff --git a/tests/wpt/web-platform-tests/worklets/idlharness.worker.js b/tests/wpt/web-platform-tests/worklets/idlharness.worker.js
deleted file mode 100644
index 827dd02c4c5..00000000000
--- a/tests/wpt/web-platform-tests/worklets/idlharness.worker.js
+++ /dev/null
@@ -1,13 +0,0 @@
-importScripts("/resources/testharness.js");
-importScripts("/resources/WebIDLParser.js", "/resources/idlharness.js");
-
-// https://drafts.css-houdini.org/worklets/
-
-promise_test(async () => {
-  const idl = await fetch('/interfaces/worklets.idl').then(r => r.text());
-
-  const idl_array = new IdlArray();
-  idl_array.add_idls(idl);
-  idl_array.test();
-}, 'worklets interfaces');
-done();