Remove AtomicStringImpl.

Source/core/dom/CheckedRadioButtons.cpp

 /*
  * Copyright (C) 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 242 matching lines @@
         return;
 
     m_nameToGroupMap->checkConsistency();
     NameToGroupMap::iterator it = m_nameToGroupMap->find(element->name().impl());
     if (it == m_nameToGroupMap->end())
         return;
     it->value->remove(element);
     if (it->value->isEmpty()) {
         // FIXME: We may skip deallocating the empty RadioButtonGroup for
         // performance improvement. If we do so, we need to change the key type
-        // of m_nameToGroupMap from AtomicStringImpl* to RefPtr<AtomicStringImpl>.
+        // of m_nameToGroupMap from StringImpl* to AtomicString.
         m_nameToGroupMap->remove(it);
         if (m_nameToGroupMap->isEmpty())
             m_nameToGroupMap.clear();
     }
 }
 
 } // namespace