implement basic infra for ResizeObserver (#31108)

tests/wpt/include.ini

@@ -206,6 +206,8 @@ skip: true
       skip: true
     [srcdoc.meta]
       skip: true
+[resize-observer]
+  skip: false
 [resource-timing]
   skip: false
 [selection]

tests/wpt/meta/html/webappapis/update-rendering/child-document-raf-order.html.ini

@@ -1,3 +1,4 @@
 [child-document-raf-order.html]
   [Ordering of steps in "Update the Rendering" - child document requestAnimationFrame order]
     expected: FAIL
+

tests/wpt/meta/resize-observer/__dir__.ini

@@ -0,0 +1 @@
+prefs: ["dom.resize_observer.enabled:true"]

tests/wpt/meta/resize-observer/calculate-depth-for-node.html.ini

@@ -0,0 +1,3 @@
+[calculate-depth-for-node.html]
+  ["Calculate depth for node" algorithm with Shadow DOM]
+    expected: FAIL

tests/wpt/meta/resize-observer/devicepixel.html.ini

@@ -0,0 +1,2 @@
+[devicepixel.html]
+  expected: FAIL

tests/wpt/meta/resize-observer/eventloop.html.ini

@@ -0,0 +1,4 @@
+[eventloop.html]
+  expected: TIMEOUT
+  [guard]
+    expected: NOTRUN

tests/wpt/meta/resize-observer/fragments.html.ini

@@ -0,0 +1,9 @@
+[fragments.html]
+  [Adding 2nd fragment]
+    expected: FAIL
+
+  [Resizing 2nd fragment]
+    expected: FAIL
+
+  [Resizing all fragments]
+    expected: FAIL

tests/wpt/meta/resize-observer/notify.html.ini

@@ -0,0 +1,7 @@
+[notify.html]
+  expected: ERROR
+  [guard]
+    expected: NOTRUN
+
+  [test2: remove/appendChild trigger notification]
+    expected: FAIL

tests/wpt/meta/resize-observer/observe.html.ini

@@ -0,0 +1,4 @@
+[observe.html]
+  expected: TIMEOUT
+  [guard]
+    expected: NOTRUN

tests/wpt/meta/resize-observer/ordering.html.ini

@@ -0,0 +1,3 @@
+[ordering.html]
+  [ResizeObserver and IntersectionObserver ordering]
+    expected: FAIL

tests/wpt/meta/resize-observer/scrollbars-2.html.ini

@@ -0,0 +1,3 @@
+[scrollbars-2.html]
+  [ResizeObserver content-box size and scrollbars]
+    expected: FAIL

tests/wpt/meta/resize-observer/scrollbars.html.ini

@@ -0,0 +1,3 @@
+[scrollbars.html]
+  [ResizeObserver content-box size and scrollbars]
+    expected: FAIL

tests/wpt/meta/resize-observer/svg-with-css-box-001.html.ini

@@ -0,0 +1,10 @@
+[svg-with-css-box-001.html]
+  expected: TIMEOUT
+  [test0: observe `foreignObject` SVG in HTML document]
+    expected: FAIL
+
+  [test1: observe inline SVG in HTML]
+    expected: FAIL
+
+  [guard]
+    expected: NOTRUN

tests/wpt/meta/resize-observer/svg-with-css-box-002.svg.ini

@@ -0,0 +1,2 @@
+[svg-with-css-box-002.svg]
+  expected: TIMEOUT

tests/wpt/meta/resize-observer/svg.html.ini

@@ -0,0 +1,34 @@
+[svg.html]
+  expected: TIMEOUT
+  [guard]
+    expected: NOTRUN
+
+  [test0: observe svg:circle]
+    expected: FAIL
+
+  [test1: observe svg:ellipse]
+    expected: FAIL
+
+  [test2: observe svg:foreignObject]
+    expected: FAIL
+
+  [test3: observe svg:image]
+    expected: FAIL
+
+  [test4: observe svg:line]
+    expected: FAIL
+
+  [test5: observe svg:path]
+    expected: FAIL
+
+  [test6: observe svg:polygon]
+    expected: FAIL
+
+  [test7: observe svg:polyline]
+    expected: FAIL
+
+  [test8: observe svg:rect]
+    expected: FAIL
+
+  [test9: observe svg:text]
+    expected: TIMEOUT