Relax aria-activedescendant validation

Removing the role check for aria-activedescendant support simplifies the
code and decreases differences with Firefox.

Bug: None
Change-Id: Ie497d29434344152d1e51d27a9301e31e332b1d9
Reviewed-on: https://chromium-review.googlesource.com/1213539Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590294}

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

@@ -2414,7 +2414,7 @@ void AXLayoutObject::HandleActiveDescendantChanged() {
     return;
 
   AXObject* focused_object = AXObjectCache().FocusedObject();
-  if (focused_object == this && SupportsARIAActiveDescendant()) {
+  if (focused_object == this) {
     AXObject* active_descendant = ActiveDescendant();
     if (active_descendant && active_descendant->IsSelectedFromFocus()) {
       // In single selection containers, selection follows focus, so a selection

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

@@ -1290,8 +1290,7 @@ bool AXObject::AncestorExposesActiveDescendant() const {
   if (!parent)
     return false;
 
-  if (parent->SupportsARIAActiveDescendant() &&
-      parent->GetAOMPropertyOrARIAAttribute(
+  if (parent->GetAOMPropertyOrARIAAttribute(
           AOMRelationProperty::kActiveDescendant)) {
     return true;
   }
@@ -1734,34 +1733,6 @@ bool AXObject::AriaCheckedIsPresent() const {
   return HasAOMPropertyOrARIAAttribute(AOMStringProperty::kChecked, result);
 }
 
-bool AXObject::SupportsARIAActiveDescendant() const {
-  // According to the ARIA Spec, all ARIA composite widgets, ARIA text boxes,
-  // ARIA groups and ARIA application should be able to expose an active descendant.
-  // Implicitly, <input> and <textarea> elements should also have this ability.
-  switch (RoleValue()) {
-    case kComboBoxGroupingRole:
-    case kComboBoxMenuButtonRole:
-    case kGridRole:
-    case kGroupRole:
-    case kListBoxRole:
-    case kMenuRole:
-    case kMenuBarRole:
-    case kRadioGroupRole:
-    case kRowRole:
-    case kSearchBoxRole:
-    case kTabListRole:
-    case kTextFieldRole:
-    case kTextFieldWithComboBoxRole:
-    case kToolbarRole:
-    case kTreeRole:
-    case kTreeGridRole:
-    case kApplicationRole:
-      return true;
-    default:
-      return false;
-  }
-}
-
 bool AXObject::SupportsARIAExpanded() const {
   switch (RoleValue()) {
     case kAlertDialogRole:

third_party/blink/renderer/modules/accessibility/ax_object.h

@@ -727,7 +727,6 @@ class MODULES_EXPORT AXObject : public GarbageCollectedFinalized<AXObject> {
   virtual bool IsRichlyEditable() const { return false; }
   bool AriaCheckedIsPresent() const;
   bool AriaPressedIsPresent() const;
-  bool SupportsARIAActiveDescendant() const;
   bool SupportsARIAAttributes() const;
   bool SupportsARIAExpanded() const;
   virtual bool SupportsARIADragging() const { return false; }