Selection follows focus/activedescendant in single selection containers

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 439 matching lines @@
   // focusable.  Check instead if the frame's selection controller is focused
   if (focused_object == this ||
       (RoleValue() == kWebAreaRole &&
        GetDocument()->GetFrame()->Selection().FrameIsFocusedAndActive()))
     return true;
 
   return false;
 }
 
 bool AXLayoutObject::IsSelected() const {
-  if (!GetLayoutObject() || !GetNode())
+  if (!GetLayoutObject() || !GetNode() || !CanSetSelectedAttribute())
     return false;
 
-  if (AOMPropertyOrARIAAttributeIsTrue(AOMBooleanProperty::kSelected))
-    return true;
+  // aria-selected overrides automatic behaviors

[David Tseng, 2017/06/06 20:58:30]

Note that this doesn't actually happen because the !CanSetSelectedAttribute()
returns early and CanSetSelectedAttribute() function never actually checks
aria-selected...

+  bool is_selected;
+  if (HasAOMPropertyOrARIAAttribute(AOMBooleanProperty::kSelected, is_selected))
+    return is_selected;
 
-  AXObjectImpl* focused_object = AxObjectCache().FocusedObject();
-  if (AriaRoleAttribute() == kListBoxOptionRole && focused_object &&
-      focused_object->ActiveDescendant() == this) {
-    return true;
-  }
-
+  // Tab item with focus in the associated tab
   if (IsTabItem() && IsTabItemSelected())
     return true;
 
-  return false;
+  // Selection follows focus, but ONLY in single selection containers,
+  // and only if aria-selected was not present to override
+
+  AXObjectImpl* container = ContainerWidget();
+  if (!container || container->IsMultiSelectable())
+    return false;
+
+  AXObjectImpl* focused_object = AxObjectCache().FocusedObject();
+  return focused_object == this ||
+         (focused_object && focused_object->ActiveDescendant() == this);
 }
 
 //
 // Whether objects are ignored, i.e. not included in the tree.
 //
 
 AXObjectInclusion AXLayoutObject::DefaultObjectInclusion(
     IgnoredReasons* ignored_reasons) const {
   // The following cases can apply to any element that's a subclass of
   // AXLayoutObject.
@@ skipping 2038 matching lines @@
 
 bool AXLayoutObject::ElementAttributeValue(
     const QualifiedName& attribute_name) const {
   if (!layout_object_)
     return false;
 
   return EqualIgnoringASCIICase(GetAttribute(attribute_name), "true");
 }
 
 }  // namespace blink