Add handling to respect role attribute in AXObjects.

Source/modules/accessibility/AXListBoxOption.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 35 matching lines @@
 
 AXListBoxOption::~AXListBoxOption()
 {
 }
 
 PassRefPtr<AXListBoxOption> AXListBoxOption::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
 {
     return adoptRef(new AXListBoxOption(layoutObject, axObjectCache));
 }
 
+AccessibilityRole AXListBoxOption::roleValue() const
+{
+    AccessibilityRole ariaRole = ariaRoleAttribute();
+    if (ariaRole != UnknownRole)
+        return ariaRole;
+    return ListBoxOptionRole;
+}
+
 bool AXListBoxOption::isEnabled() const
 {
     if (!node())
         return false;
 
     if (equalIgnoringCase(getAttribute(aria_disabledAttr), "true"))
         return false;
 
     if (toElement(node())->hasAttribute(disabledAttr))
         return false;
@@ skipping 95 matching lines @@
     unsigned length = listItems.size();
     for (unsigned i = 0; i < length; i++) {
         if (listItems[i] == node())
             return i;
     }
 
     return -1;
 }
 
 } // namespace blink