Roll back code that serialized at the CSS block level due to performance.

crrev.com/c/1062661 made it so that any time an accessibility node changes,
we re-serialize the entire CSS block it's contained in - while this fixed
some correctness issues, it introduced a performance regression that's
too significant to ignore.

This change rolls back the fix for now until we can find a way to fix it
that doesn't impact performance.

TBR=dtseng@chromium.org

Bug: 868830, 865621, 843746
Change-Id: I900a4e6ba796608974e881f091b99b0d45c09536
Reviewed-on: https://chromium-review.googlesource.com/1174851Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583182}

content/browser/accessibility/line_layout_browsertest.cc

@@ -58,8 +58,10 @@ class AccessibilityLineLayoutBrowserTest : public ContentBrowserTest {
   }
 };
 
+// http://crbug.com/868830 - the patch that enabled this test to pass
+// caused a performance regression.
 IN_PROC_BROWSER_TEST_F(AccessibilityLineLayoutBrowserTest,
-                       WholeBlockIsUpdated) {
+                       DISABLED_WholeBlockIsUpdated) {
   ASSERT_TRUE(embedded_test_server()->Start());
 
   AccessibilityNotificationWaiter waiter(shell()->web_contents(),

content/renderer/accessibility/render_accessibility_impl.cc

@@ -450,17 +450,6 @@ void RenderAccessibilityImpl::SendPendingAccessibilityEvents() {
 
     bundle.events.push_back(event);
 
-    // Whenever there's a change to an inline node, it's important to
-    // invalidate the whole surrounding block so that we have the full
-    // information about the line layout.
-    auto block = obj;
-    while (!block.IsDetached() && (block.ComputedStyleDisplay() != "block" ||
-                                   block.AccessibilityIsIgnored())) {
-      block = block.ParentObject();
-    }
-    if (!block.IsDetached() && !block.Equals(obj))
-      serializer_.InvalidateSubtree(block);
-
     // Whenever there's a change within a table, invalidate the
     // whole table so that row and cell indexes are recomputed.
     ax::mojom::Role role = AXRoleFromBlink(obj.Role());

content/test/data/accessibility/event/aria-combo-box-next-expected-win.txt

 EVENT_OBJECT_FOCUS on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE 3 of 3
 EVENT_OBJECT_SELECTION on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE 3 of 3
 EVENT_OBJECT_SELECTIONWITHIN on <ul#list> role=ROLE_SYSTEM_LIST IA2_STATE_VERTICAL
-EVENT_OBJECT_STATECHANGE on <li#option2> role=ROLE_SYSTEM_LISTITEM name="Orange" FOCUSED,FOCUSABLE,SELECTABLE 2 of 3
 EVENT_OBJECT_STATECHANGE on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE 3 of 3
 IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on <input> role=ROLE_SYSTEM_COMBOBOX EXPANDED,FOCUSABLE,HASPOPUP IA2_STATE_EDITABLE,IA2_STATE_SELECTABLE_TEXT,IA2_STATE_SINGLE_LINE,IA2_STATE_SUPPORTS_AUTOCOMPLETION
\ No newline at end of file

content/test/data/accessibility/event/listbox-next-expected-win.txt

 EVENT_OBJECT_FOCUS on <option> role=ROLE_SYSTEM_LISTITEM name="Orange" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE 2 of 3
-EVENT_OBJECT_SELECTION on <option> role=ROLE_SYSTEM_LISTITEM name="Orange" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE 2 of 3
+EVENT_OBJECT_SELECTION on <option> role=ROLE_SYSTEM_LISTITEM name="Orange" SELECTED,FOCUSABLE,SELECTABLE 2 of 3
 EVENT_OBJECT_SELECTIONWITHIN on <select> role=ROLE_SYSTEM_LIST FOCUSABLE IA2_STATE_VERTICAL
 EVENT_OBJECT_STATECHANGE on <option> role=ROLE_SYSTEM_LISTITEM name="Apple" FOCUSABLE,SELECTABLE 1 of 3
-EVENT_OBJECT_STATECHANGE on <option> role=ROLE_SYSTEM_LISTITEM name="Orange" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE 2 of 3
+EVENT_OBJECT_STATECHANGE on <option> role=ROLE_SYSTEM_LISTITEM name="Orange" SELECTED,FOCUSABLE,SELECTABLE 2 of 3
 IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on <select> role=ROLE_SYSTEM_LIST FOCUSABLE IA2_STATE_VERTICAL
\ No newline at end of file

content/test/data/accessibility/event/menulist-collapse-expected-mac.txt

-AXFocusedUIElementChanged on AXPopUpButton
 AXValueChanged on AXPopUpButton
\ No newline at end of file

content/test/data/accessibility/event/menulist-collapse-expected-win.txt

-EVENT_OBJECT_FOCUS on <select> role=ROLE_SYSTEM_COMBOBOX FOCUSED,COLLAPSED,FOCUSABLE,HASPOPUP
-EVENT_OBJECT_STATECHANGE on <option> role=ROLE_SYSTEM_LISTITEM name="Apple" INVISIBLE,FOCUSABLE,SELECTABLE 1 of 3
-EVENT_OBJECT_VALUECHANGE on <select> role=ROLE_SYSTEM_COMBOBOX FOCUSED,COLLAPSED,FOCUSABLE,HASPOPUP
+EVENT_OBJECT_STATECHANGE on <option> role=ROLE_SYSTEM_LISTITEM name="Apple" FOCUSED,INVISIBLE,FOCUSABLE,SELECTABLE 1 of 3
+EVENT_OBJECT_VALUECHANGE on <select> role=ROLE_SYSTEM_COMBOBOX COLLAPSED,FOCUSABLE,HASPOPUP
\ No newline at end of file
-IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on role=ROLE_SYSTEM_LIST INVISIBLE
\ No newline at end of file

content/test/data/accessibility/event/menulist-focus-expected-mac.txt

-AXFocusedUIElementChanged on AXMenuItem AXValue="Apple"
-AXMenuItemSelected on AXMenuItem AXValue="Apple"
+AXFocusedUIElementChanged on AXPopUpButton AXValue="Apple"
\ No newline at end of file
\ No newline at end of file

content/test/data/accessibility/event/menulist-focus-expected-win.txt

-EVENT_OBJECT_FOCUS on <option> role=ROLE_SYSTEM_LISTITEM name="Apple" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE 1 of 3
-IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on role=ROLE_SYSTEM_LIST INVISIBLE
+EVENT_OBJECT_FOCUS on <select> role=ROLE_SYSTEM_COMBOBOX value="Apple" FOCUSED,COLLAPSED,FOCUSABLE,HASPOPUP
\ No newline at end of file
\ No newline at end of file