Remove AtomicStringImpl.

Source/core/dom/TreeScope.cpp

 /*
  * Copyright (C) 2011 Google Inc. All Rights Reserved.
  * Copyright (C) 2012 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 159 matching lines @@
             return 0;
 
         node = node->shadowHost();
     }
 
     return 0;
 }
 
 void TreeScope::addImageMap(HTMLMapElement* imageMap)
 {
-    AtomicStringImpl* name = imageMap->getName().impl();
+    StringImpl* name = imageMap->getName().impl();
     if (!name)
         return;
     if (!m_imageMapsByName)
         m_imageMapsByName = adoptPtr(new DocumentOrderedMap);
     m_imageMapsByName->add(name, imageMap);
 }
 
 void TreeScope::removeImageMap(HTMLMapElement* imageMap)
 {
     if (!m_imageMapsByName)
         return;
-    AtomicStringImpl* name = imageMap->getName().impl();
+    StringImpl* name = imageMap->getName().impl();
     if (!name)
         return;
     m_imageMapsByName->remove(name, imageMap);
 }
 
 HTMLMapElement* TreeScope::getImageMap(const String& url) const
 {
     if (url.isNull())
         return 0;
     if (!m_imageMapsByName)
@@ skipping 283 matching lines @@
 {
     ASSERT(scope);
     for (; scope; scope = scope->parentTreeScope()) {
         if (scope == this)
             return true;
     }
     return false;
 }
 
 } // namespace WebCore