Implement computedRole and computedName (behind a flag)

Source/core/dom/AXObjectCache.cpp

 /*
  * Copyright (C) 2008, 2009, 2010 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 22 matching lines @@
 namespace blink {
 
 AXObjectCache::AXObjectCache()
 {
 }
 
 AXObjectCache::~AXObjectCache()
 {
 }
 
+ScopedAXObjectCache::ScopedAXObjectCache(Document& document)
+    : m_document(document)
+    , m_cache(0)
+{
+    if (AXObjectCache* existingCache = document.axObjectCache()) {
+        m_cache = existingCache;
+        m_isScoped = false;
+    } else {
+        m_isScoped = true;
+        m_cache = AXObjectCache::create(m_document);
+    }
+}
+
+ScopedAXObjectCache::~ScopedAXObjectCache()
+{
+    if (m_isScoped)
+        delete m_cache;
+}
+
+AXObjectCache* ScopedAXObjectCache::get()
+{
+    ASSERT(m_cache);
+    return m_cache;
+}
+
+AXObjectCache* ScopedAXObjectCache::operator->()
+{
+    return get();
+}
+
 } // namespace blink