Revert "Reland "DL: Don't include skip-viewport-activation subtrees in the AX tree""

This reverts commit 0b25b17e.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 742520 as the
culprit for flakes in the build cycles as shown on:
https://analysis.chromium.org/p/chromium/flake-portal/analysis/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vMGIyNWIxN2VkYThlMWY0YjRiN2MxMDI0ZmRjZWQ2Mjg0Nzc5Y2RlYQw

Sample Failed Build: https://ci.chromium.org/b/8888021964038070960

Sample Failed Step: content_browsertests

Sample Flaky Test: All/DumpAccessibilityTreeTest.DisplayLockingViewportActivation/blink

Original change's description:
> Reland "DL: Don't include skip-viewport-activation subtrees in the AX tree"
> 
> This is a reland of c08274e9
> 
> The CL was previously reverted because the viewport activation test is
> flaky, probably due to uncertain timing of near-the-viewport activation.
> I've updated the test to only test for in-the-viewport activation,
> I'll investigate further on why it's flaky for near-the-viewport
> (manual testing shows activation happens consistently).
> 
> SHERIFFS: please don't revert this CL if it introduces a new flaky test.
> Instead, please disable them and I'll investigate.
> 
> Original change's description:
> > DL: Don't include skip-viewport-activation subtrees in the AX tree
> >
> > Now both render-subtree: skip-viewport-activation and skip-activation
> > subtrees are not in the AX subtree at all, as discussed in
> > https://github.com/WICG/display-locking/issues/102#issuecomment-564205445
> >
> > Now only render-subtree:invisible subtrees are in the AX tree, and they
> > are automatically marked as offscreen because the nodes are activated
> > when they are on screen.
> >
> > Bug: 1001930
> > Change-Id: I1de511672f60078a02b3ddf3d989f2da1c44ae9d
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2028883
> > Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
> > Reviewed-by: vmpstr <vmpstr@chromium.org>
> > Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
> > Commit-Queue: Rakina Zata Amni <rakina@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#740531}
> 
> Bug: 1001930
> Change-Id: Icdf43cff86ade7e7e8f2aee76933dfc51e3f022c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2054649
> Reviewed-by: vmpstr <vmpstr@chromium.org>
> Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
> Commit-Queue: Rakina Zata Amni <rakina@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#742520}


Change-Id: I9258a82fa5a36921963dda0d12ce6efde1895e4b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1001930
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063667
Cr-Commit-Position: refs/heads/master@{#742651}

content/browser/accessibility/dump_accessibility_tree_browsertest.cc

@@ -2272,17 +2272,22 @@ IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest, DeleteSelectionCrash) {
   RunHtmlTest(FILE_PATH_LITERAL("delete-selection-crash.html"));
 }
 
+IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest, DisplayLockingActivatable) {
+  RunDisplayLockingTest(FILE_PATH_LITERAL("activatable.html"));
+}
+
 IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest,
-                       DisplayLockingNonActivatable) {
-  RunDisplayLockingTest(FILE_PATH_LITERAL("non-activatable.html"));
+                       DisplayLockingActivatableActivated) {
+  RunDisplayLockingTest(FILE_PATH_LITERAL("activatable-activated.html"));
 }
 
 IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest,
-                       DisplayLockingViewportActivation) {
-  RunDisplayLockingTest(FILE_PATH_LITERAL("viewport-activation.html"));
+                       DisplayLockingNonActivatable) {
+  RunDisplayLockingTest(FILE_PATH_LITERAL("non-activatable.html"));
 }
 
-IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest, DisplayLockingAll) {
+// crbug.com/1043480: disabled due to flakiness.
+IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest, DISABLED_DisplayLockingAll) {
   RunDisplayLockingTest(FILE_PATH_LITERAL("all.html"));
 }
 

content/test/data/accessibility/display-locking/activatable-activated-expected-blink.txt

+rootWebArea
+++genericContainer ignored
+++++genericContainer ignored
+++++++genericContainer
+++++++++genericContainer
+++++++++++staticText name='child'
+++++++++++++inlineTextBox name='child'
+++++++++genericContainer
+++++++++++staticText name='nested locked element!'
+++++++++genericContainer

content/test/data/accessibility/display-locking/activatable-activated.html

+<!--
+@BLINK-ALLOW:offscreen
+-->
+<div>
+  <div id="locked" rendersubtree="invisible skip-viewport-activation">
+    <div>child</div>
+    <div id="nested" rendersubtree="invisible skip-viewport-activation">nested locked element!</div>
+    <div id="nonActivatable" rendersubtree="invisible skip-activation">nested non activatable locked element</div>
+  </div>
+</div>
+
+<script>
+  // Force layout, then activate.
+  locked.getBoundingClientRect();
+  locked.scrollIntoView();
+</script>

content/test/data/accessibility/display-locking/activatable-expected-blink.txt

+rootWebArea
+++genericContainer ignored
+++++genericContainer ignored
+++++++genericContainer
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++++staticText name='child'
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++++staticText name='nested locked element!'
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++staticText name='<newline>  '

content/test/data/accessibility/display-locking/activatable.html

+<!--
+@BLINK-ALLOW:offscreen
+-->
+<div>
+  <div id="locked" rendersubtree="invisible skip-viewport-activation">
+    <div>child</div>
+    <div id="nested" rendersubtree="invisible skip-viewport-activation">nested locked element!</div>
+    <div id="nonActivatable" rendersubtree="invisible skip-activation">nested non activatable locked element</div>
+  </div>
+</div>

content/test/data/accessibility/display-locking/all-committed-expected-blink.txt

@@ -2,31 +2,19 @@ rootWebArea
 ++genericContainer ignored
 ++++genericContainer ignored
 ++++++genericContainer
-++++++++staticText name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++++++inlineTextBox name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++genericContainer offscreen
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='child text will be in AX tree but without layout'
-++++++++++++inlineTextBox offscreen name='child text will be in AX tree but without layout'
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='nested activatable locked element will be in AX tree but without layout'
-++++++++++++inlineTextBox offscreen name='nested activatable locked element will be in AX tree but without layout'
-++++++++staticText offscreen name='normal text 1'
-++++++++++inlineTextBox offscreen name='normal text 1'
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='nested non-viewport-activatable locked element will not be in AX tree'
-++++++++++++inlineTextBox offscreen name='nested non-viewport-activatable locked element will not be in AX tree'
-++++++++staticText offscreen name='normal text 2'
-++++++++++inlineTextBox offscreen name='normal text 2'
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='nested non-activatable locked element will not be in AX tree'
-++++++++++++inlineTextBox offscreen name='nested non-activatable locked element will not be in AX tree'
-++++++++staticText offscreen name='normal text 3'
-++++++++++inlineTextBox offscreen name='normal text 3'
-++++++++presentational ignored offscreen
-++++++++++staticText offscreen name='role=presentation item will be in AX tree'
-++++++++++++inlineTextBox offscreen name='role=presentation item will be in AX tree'
-++++++++genericContainer ignored invisible offscreen name='visibility:hidden text will be in AX tree'
-++++++++genericContainer ignored invisible offscreen
-++++++++++staticText ignored invisible offscreen name='aria-hidden text will be in AX tree'
-
+++++++++genericContainer
+++++++++++staticText name='child'
+++++++++++++inlineTextBox name='child'
+++++++++genericContainer
+++++++++++staticText name='nested locked element!'
+++++++++++++inlineTextBox name='nested locked element!'
+++++++++genericContainer
+++++++++++staticText name='nested non activatable locked element'
+++++++++++++inlineTextBox name='nested non activatable locked element'
+++++++++presentational ignored
+++++++++++listItem ignored
+++++++++++++staticText name='role=presentation item'
+++++++++++++++inlineTextBox name='role=presentation item'
+++++++++genericContainer ignored invisible name='visibility:hidden text'
+++++++++genericContainer ignored invisible
+++++++++++staticText ignored invisible name='aria-hidden text'

content/test/data/accessibility/display-locking/all-committed.html

@@ -2,29 +2,20 @@
 @BLINK-ALLOW:offscreen
 -->
 <div>
-  <div style="height:10000px;">spacer so that everything below will be offscreen (and won't get viewport-activated)</div>
-  <div id="locked" rendersubtree="invisible">
-    <div>child text will be in AX tree but without layout</div>
-    <div id="nested" rendersubtree="invisible">
-      nested activatable locked element will be in AX tree but without layout
-    </div>
-    normal text 1
-    <div id="nonViewportActivatable" rendersubtree="invisible skip-viewport-activation">
-      nested non-viewport-activatable locked element will not be in AX tree
-    </div>
-    normal text 2
-    <div id="nonActivatable" rendersubtree="invisible skip-activation">
-      nested non-activatable locked element will not be in AX tree
-    </div>
-    normal text 3
+  <div id="locked" rendersubtree="invisible skip-viewport-activation">
+    <div>child</div>
+    <div id="nested" rendersubtree="invisible skip-viewport-activation">nested locked element!</div>
+    <div id="nonActivatable" rendersubtree="invisible skip-activation">nested non activatable locked element</div>
     <!--
       TODO(rakina): Make display:none, visibility:hidden, aria-hidden nodes
       in locked subtrees get ignored for accessibility/marked invisible.
     -->
-    <div style="display:none;">display:none text will be in AX tree</div>
-    <div role="presentation">role=presentation item will be in AX tree</div>
-    <div style="visibility:hidden;">visibility:hidden text will be in AX tree</div>
-    <div aria-hidden="true">aria-hidden text will be in AX tree</div>
+    <div style="display:none;">display:none text</div>
+    <ul role="presentation">
+      <li>role=presentation item</li>
+    </ul>
+    <div style="visibility:hidden;">visibility:hidden text</div>
+    <div aria-hidden="true">aria-hidden text</div>
   </div>
 </div>
 
@@ -32,6 +23,5 @@
   // Force layout, then commit everything.
   locked.removeAttribute("rendersubtree");
   nested.removeAttribute("rendersubtree");
-  nonViewportActivatable.removeAttribute("rendersubtree");
   nonActivatable.removeAttribute("rendersubtree");
 </script>

content/test/data/accessibility/display-locking/all-expected-blink.txt

@@ -2,30 +2,27 @@ rootWebArea
 ++genericContainer ignored
 ++++genericContainer ignored
 ++++++genericContainer
-++++++++staticText name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++++++inlineTextBox name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++genericContainer offscreen
-++++++++staticText offscreen name='<newline>    '
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='child text will be in AX tree but without layout'
-++++++++staticText offscreen name='<newline>    '
-++++++++genericContainer offscreen
-++++++++++staticText offscreen name='<newline>      nested activatable locked element will be in AX tree but without layout<newline>    '
-++++++++staticText offscreen name='<newline>    normal text 1<newline>    '
-++++++++genericContainer offscreen
-++++++++staticText offscreen name='<newline>    normal text 2<newline>    '
-++++++++genericContainer offscreen
-++++++++staticText offscreen name='<newline>    normal text 3<newline>    '
-++++++++staticText offscreen name='<newline>    '
-++++++++genericContainer invisible offscreen
-++++++++++staticText offscreen name='display:none text will be in AX tree'
-++++++++staticText offscreen name='<newline>    '
-++++++++staticText offscreen name='role=presentation item will be in AX tree'
-++++++++staticText offscreen name='<newline>    '
-++++++++genericContainer invisible offscreen
-++++++++++staticText offscreen name='visibility:hidden text will be in AX tree'
-++++++++staticText offscreen name='<newline>    '
-++++++++genericContainer invisible offscreen
-++++++++++staticText invisible offscreen name='aria-hidden text will be in AX tree'
-++++++++staticText offscreen name='<newline>  '
-
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++++staticText name='child'
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++++staticText name='nested locked element!'
+++++++++staticText name='<newline>    '
+++++++++genericContainer
+++++++++staticText name='<newline>    '
+++++++++staticText name='<newline>    '
+++++++++genericContainer invisible
+++++++++++staticText name='display:none text'
+++++++++staticText name='<newline>    '
+++++++++staticText name='<newline>      '
+++++++++genericContainer
+++++++++++staticText name='role=presentation item'
+++++++++staticText name='<newline>    '
+++++++++staticText name='<newline>    '
+++++++++genericContainer invisible
+++++++++++staticText name='visibility:hidden text'
+++++++++staticText name='<newline>    '
+++++++++genericContainer invisible
+++++++++++staticText invisible name='aria-hidden text'
+++++++++staticText name='<newline>  '

content/test/data/accessibility/display-locking/all.html

@@ -2,28 +2,19 @@
 @BLINK-ALLOW:offscreen
 -->
 <div>
-  <div style="height:10000px;">spacer so that everything below will be offscreen (and won't get viewport-activated)</div>
-  <div id="locked" rendersubtree="invisible">
-    <div>child text will be in AX tree but without layout</div>
-    <div id="nested" rendersubtree="invisible">
-      nested activatable locked element will be in AX tree but without layout
-    </div>
-    normal text 1
-    <div id="nonViewportActivatable" rendersubtree="invisible skip-viewport-activation">
-      nested non-viewport-activatable locked element will not be in AX tree
-    </div>
-    normal text 2
-    <div id="nonActivatable" rendersubtree="invisible skip-activation">
-      nested non-activatable locked element will not be in AX tree
-    </div>
-    normal text 3
+  <div id="locked" rendersubtree="invisible skip-viewport-activation">
+    <div>child</div>
+    <div id="nested" rendersubtree="invisible skip-viewport-activation">nested locked element!</div>
+    <div id="nonActivatable" rendersubtree="invisible skip-activation">nested non activatable locked element</div>
     <!--
       TODO(rakina): Make display:none, visibility:hidden, aria-hidden nodes
       in locked subtrees get ignored for accessibility/marked invisible.
     -->
-    <div style="display:none;">display:none text will be in AX tree</div>
-    <div role="presentation">role=presentation item will be in AX tree</div>
-    <div style="visibility:hidden;">visibility:hidden text will be in AX tree</div>
-    <div aria-hidden="true">aria-hidden text will be in AX tree</div>
+    <div style="display:none;">display:none text</div>
+    <ul role="presentation">
+      <li>role=presentation item</li>
+    </ul>
+    <div style="visibility:hidden;">visibility:hidden text</div>
+    <div aria-hidden="true">aria-hidden text</div>
   </div>
 </div>

content/test/data/accessibility/display-locking/viewport-activation-expected-blink.txt

-rootWebArea
-++genericContainer ignored
-++++genericContainer ignored
-++++++genericContainer offscreen
-++++++++staticText offscreen name='initial spacer, will initially make everything below this far away from the viewport'
-++++++++++inlineTextBox offscreen name='initial spacer, will initially make everything below this far away from the viewport'
-++++++genericContainer
-++++++++staticText name='This text will get viewport-activated because it's in the viewport, and will be in AX tree with layout.'
-++++++++++inlineTextBox name='This text will get viewport-activated because it's in the viewport, and will be in AX tree with layout.'
-++++++++genericContainer
-++++++++++staticText name='This too!'
-++++++++++++inlineTextBox name='This too!'
-++++++genericContainer
-++++++++staticText name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++++++inlineTextBox name='spacer so that everything below will be offscreen (and won't get viewport-activated)'
-++++++genericContainer
-++++++++staticText offscreen name='<newline>    This text will not get viewport-activated, and will be in AX tree but without layout.<newline>  '
-++++++genericContainer offscreen
-++++++++staticText offscreen name='doneActivating'
-++++++++++inlineTextBox offscreen name='doneActivating'
-

content/test/data/accessibility/display-locking/viewport-activation.html

-<!--
-@BLINK-ALLOW:offscreen
-@WAIT-FOR:doneActivating
--->
-<div>
-  <div id="initialSpacer" style="height: 10000px;">
-    initial spacer, will initially make everything below this far away from the viewport
-  </div>
-  <div id="inViewport" rendersubtree="invisible">
-    This text will get viewport-activated because it's in the viewport, and will be in AX tree with layout.
-    <div id="nestedInViewport" rendersubtree="invisible">
-      This too!
-    </div>
-  </div>
-  <div style="height:10000px;">
-    spacer so that everything below will be offscreen (and won't get viewport-activated)
-  </div>
-  <div id="wayBelowViewport" rendersubtree="invisible">
-    This text will not get viewport-activated, and will be in AX tree but without layout.
-  </div>
-  <div id="statusDiv"></div>
-</div>
-<script>
-  inViewport.getBoundingClientRect();
-  inViewport.scrollIntoView();
-  // Viewport activation happens on the next frame, so we'll wait until then before ending.
-  window.requestAnimationFrame(() => {
-    window.requestAnimationFrame(() => {
-      statusDiv.innerText = "doneActivating";
-    });
-  });
-</script>

third_party/blink/renderer/core/display_lock/display_lock_context.h

@@ -45,8 +45,7 @@ enum class DisplayLockActivationReason {
   // Shorthands
   kViewport = static_cast<uint16_t>(kSelection) |
               static_cast<uint16_t>(kUserFocus) |
-              static_cast<uint16_t>(kViewportIntersection) |
-              static_cast<uint16_t>(kAccessibility),
+              static_cast<uint16_t>(kViewportIntersection),
   kAny = static_cast<uint16_t>(kAccessibility) |
          static_cast<uint16_t>(kFindInPage) |
          static_cast<uint16_t>(kFragmentNavigation) |

third_party/blink/renderer/core/display_lock/display_lock_utilities.cc

@@ -298,24 +298,23 @@ Element* DisplayLockUtilities::NearestLockedExclusiveAncestor(
   return nullptr;
 }
 
-bool DisplayLockUtilities::IsInUnlockedOrActivatableSubtree(
-    const Node& node,
-    DisplayLockActivationReason activation_reason) {
+bool DisplayLockUtilities::IsInNonActivatableLockedSubtree(const Node& node) {
   if (!RuntimeEnabledFeatures::DisplayLockingEnabled(
           node.GetExecutionContext()) ||
       node.GetDocument().LockedDisplayLockCount() == 0 ||
       node.GetDocument().DisplayLockBlockingAllActivationCount() == 0 ||
       !node.CanParticipateInFlatTree()) {
-    return true;
+    return false;
   }
 
   for (auto* element = NearestLockedExclusiveAncestor(node); element;
        element = NearestLockedExclusiveAncestor(*element)) {
-    if (!element->GetDisplayLockContext()->IsActivatable(activation_reason)) {
-      return false;
+    if (!element->GetDisplayLockContext()->IsActivatable(
+            DisplayLockActivationReason::kAny)) {
+      return true;
     }
   }
-  return true;
+  return false;
 }
 
 bool DisplayLockUtilities::IsInLockedSubtreeCrossingFrames(

third_party/blink/renderer/core/display_lock/display_lock_utilities.h

@@ -70,22 +70,8 @@ class CORE_EXPORT DisplayLockUtilities {
   static Element* NearestLockedInclusiveAncestor(const LayoutObject& object);
   static Element* NearestLockedExclusiveAncestor(const LayoutObject& object);
 
-  // Returns true if |node| is not in a locked subtree, or if it's possible to
-  // activate all of the locked ancestors for |activation_reason|.
-  static bool IsInUnlockedOrActivatableSubtree(
-      const Node& node,
-      DisplayLockActivationReason activation_reason =
-          DisplayLockActivationReason::kAny);
-
-  // Returns true if |node| is in a locked subtree, and at least one of its
-  // locked ancestors can't be activated with |activation_reason|. In other
-  // words, this node should be treated as if it's not in the tree for
-  // |activation_reason|.
-  static bool ShouldIgnoreNodeDueToDisplayLock(
-      const Node& node,
-      DisplayLockActivationReason activation_reason) {
-    return !IsInUnlockedOrActivatableSubtree(node, activation_reason);
-  }
+  // Whether this node has non-activatable locked exclusive ancestors or not.
+  static bool IsInNonActivatableLockedSubtree(const Node& node);
 
   // Returns true if the element is in a locked subtree (or is self-locked with
   // no self-updates). This crosses frames while navigating the ancestor chain.

third_party/blink/renderer/modules/accessibility/ax_node_object.cc

@@ -361,8 +361,7 @@ bool AXNodeObject::ComputeAccessibilityIsIgnored(
   }
 
   if (DisplayLockUtilities::NearestLockedExclusiveAncestor(*GetNode())) {
-    if (DisplayLockUtilities::ShouldIgnoreNodeDueToDisplayLock(
-            *GetNode(), DisplayLockActivationReason::kAccessibility)) {
+    if (DisplayLockUtilities::IsInNonActivatableLockedSubtree(*GetNode())) {
       if (ignored_reasons)
         ignored_reasons->push_back(IgnoredReason(kAXNotRendered));
       return true;

third_party/blink/web_tests/inspector-protocol/accessibility/accessibility-getFullAXTree-display-locked-expected.txt

@@ -2,9 +2,6 @@ Tests accessibility values of display locked nodes
 
 WebArea
   generic
-    generic
-      text "spacer"
-        InlineTextBox
     generic
       text "locked"
       generic
@@ -20,7 +17,6 @@ WebArea
         text "nested"
       text "text"
     generic
-    generic
     generic
       text "normal text"
         InlineTextBox

third_party/blink/web_tests/inspector-protocol/accessibility/accessibility-getFullAXTree-display-locked.js

 (async function(testRunner) {
-  var {page, session, dp} = await testRunner.startHTML(
-      `
-    <div style='height: 10000px;'>spacer</div>
-    <div id='activatable' rendersubtree='invisible'>
+  var {page, session, dp} = await testRunner.startHTML(`
+    <div id='activatable' rendersubtree='invisible skip-viewport-activation'>
       locked
       <div id='child'>
         child
         <div id='grandChild'>grandChild</div>
       </div>
       <div id='invisible' style='display:none'>invisible</div>
-      <div id='nested' rendersubtree='invisible'>nested</div>
+      <div id='nested' rendersubtree='invisible skip-viewport-activation'>nested</div>
       text
     </div>
-    <div id='nonViewportActivatable' rendersubtree='invisible skip-viewport-activation'>nonViewportActivatable text</div>
     <div id='nonActivatable' rendersubtree='invisible skip-activation'>nonActivatable text</div>
     <div id='normal'>normal text</div>
-  `,
-      'Tests accessibility values of display locked nodes');
+  `, 'Tests accessibility values of display locked nodes');
   const dumpAccessibilityNodesFromList =
       (await testRunner.loadScript('../resources/accessibility-dumpAccessibilityNodesFromList.js'))(testRunner, session);