[a11y] [Interop] Ignore ARIA roles that lack required parent context

According to the CORE-AAM and HTML-AAM specifications, if an explicit
ARIA role token (like listitem or option) is used on an element but it
is not contained within its required parent context (e.g., a listitem
must be owned by a list; an option must be owned by a listbox), the
user agent must ignore the role token and fallback to the next role
in the string or the native host element's role.

This CL fixes this in Blink accessibility by implementing a
context-aware role determination loop:
1. Implement AXObject::HasRequiredParentContext() to verify if listitem
   or option elements have a valid owner, checking both DOM parent
   chain traversal (reentrancy-free) and the relation cache (for
   aria-owns).
2. Implement AXObject::FirstValidRoleInRoleStringWithContext() to
   iterate through all role attribute tokens and return the first valid
   role that satisfies its parent context. Ensure empty tokens
   resulting from whitespace-only roles are safely skipped to avoid
   fatal C++ DCHECK failures.
3. Update AXObject::DetermineAriaRole() to use the new context-valid
   role, meaning orphaned listitems and options now cleanly fallback.
4. Add a public AXRelationCache* RelationCache() getter to
   AXObjectCacheImpl for AXObject's checks.
5. Add a public AXObject::UpdateRole() to re-evaluate and cache the
   role in place when its required parent context changes dynamically
   (e.g., via aria-owns reparenting inside MapOwnedChildren()).
6. Support presentational containers. Update DOM parent walking loops
   in IsOrphanedListItem() and IsOrphanedOption() to safely skip over
   ignored, presentational wrapper elements (role="presentation" or
   role="none").
7. Add C++ unit tests in ax_object_test.cc to cover orphaned role
   fallbacks, aria-owns allowed roles, and presentational skips.
8. Update focusgroup unittests in ax_node_object_test.cc to wrap
   explicit listitems in valid role="list" parents so they are
   compliant and not orphans.
9. Update layout tests in web_tests/accessibility/ by wrapping
   orphaned option elements in valid role="listbox" containers,
   and update expected baseline text files.
10. Update DumpAccessibility browser tests in content/test/data/ and
    focusgroup WPT layout tests in web_tests/ by wrapping orphaned
    elements in valid list/listbox containers, and regenerate
    expected test baseline dumps (including Blink, AuraLinux, and Mac
    platforms).
11. Update AXTreeDistiller browser tests mock HTML to wrap orphaned
    listitems in a valid list container.

This fixes WPT failures in roles-generic.html,
list-roles.tentative.html, and listbox-roles.tentative.html.

Bug: 341369184, 341362249
Change-Id: I04f17e398e0e61148375a96456899241ba69c969
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7841776
Reviewed-by: David Grogan <dgrogan@chromium.org>
Commit-Queue: Lucas Radaelli <lucasradaelli@google.com>
Reviewed-by: Jacques Newman <janewman@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1631553}

Author: lucasradaelli

html/interaction/focus/focusgroup/tentative/ax-role-inference-children.html

@@ -37,7 +37,9 @@
 
 <!-- Explicit child role (should not be overridden) -->
 <div id=fgExplicitChild focusgroup="tablist">
-  <span id="explicitChild" tabindex=0 role=listitem>List Item</span>
+  <div role="list">
+    <span id="explicitChild" tabindex=0 role=listitem>List Item</span>
+  </div>
 </div>
 
 <!-- Native child semantics (link) should be preserved -->
@@ -72,7 +74,9 @@
 
 <!-- Button child with explicit role should be preserved -->
 <div id=fgButtonExplicit focusgroup="tablist">
-  <button tabindex=0 id=buttonExplicitChild role="listitem">List Item</button>
+  <div role="list">
+    <button tabindex=0 id=buttonExplicitChild role="listitem">List Item</button>
+  </div>
 </div>
 
 <!-- Popup button child should be inferred (menu) -->
@@ -97,7 +101,9 @@
 
 <!-- Popup button with explicit role should be preserved -->
 <div id=fgPopupButtonExplicit focusgroup="menubar">
-  <button tabindex=0 id=popupButtonExplicitChild aria-haspopup="menu" role="listitem">List Item</button>
+  <div role="list">
+    <button tabindex=0 id=popupButtonExplicitChild aria-haspopup="menu" role="listitem">List Item</button>
+  </div>
 </div>
 
 <!-- aria-haspopup="listbox" also produces kPopUpButton; should infer menuitem -->