Add isExpanded() API to WebAXObject.h to get aria-expanded attribute.

Source/core/accessibility/AXObject.cpp

 /*
  * Copyright (C) 2008, 2009, 2011 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 228 matching lines @@
     case TabRole:
     case TextAreaRole:
     case TextFieldRole:
     case ToggleButtonRole:
         return true;
     default:
         return false;
     }
 }
 
-bool AXObject::isExpanded() const
-{
-    if (equalIgnoringCase(getAttribute(aria_expandedAttr), "true"))
-        return true;
-
-    return false;
-}
-
 bool AXObject::accessibilityIsIgnored() const
 {
     AXObjectCache* cache = axObjectCache();
     if (!cache)
         return true;
 
     AXComputedObjectAttributeCache* attributeCache = cache->computedObjectAttributeCache();
     if (attributeCache) {
         AXObjectInclusion ignored = attributeCache->getIgnored(axObjectID());
         switch (ignored) {
@@ skipping 657 matching lines @@
         return ToggleButtonRole;
     if (ariaHasPopup())
         return PopUpButtonRole;
     // We don't contemplate RadioButtonRole, as it depends on the input
     // type.
 
     return ButtonRole;
 }
 
 } // namespace blink