Remove AtomicStringImpl.

Source/core/editing/MarkupAccumulator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010 Google 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 268 matching lines @@
     return true;
 }
 
 void MarkupAccumulator::appendNamespace(StringBuilder& result, const AtomicString& prefix, const AtomicString& namespaceURI, Namespaces& namespaces)
 {
     namespaces.checkConsistency();
     if (namespaceURI.isEmpty())
         return;
 
     // Use emptyAtoms's impl() for both null and empty strings since the HashMap can't handle 0 as a key
-    AtomicStringImpl* pre = prefix.isEmpty() ? emptyAtom.impl() : prefix.impl();
-    AtomicStringImpl* foundNS = namespaces.get(pre);
+    StringImpl* pre = prefix.isEmpty() ? emptyAtom.impl() : prefix.impl();
+    StringImpl* foundNS = namespaces.get(pre);
     if (foundNS != namespaceURI.impl()) {
         namespaces.set(pre, namespaceURI.impl());
         result.append(' ');
         result.append(xmlnsAtom.string());
         if (!prefix.isEmpty()) {
             result.append(':');
             result.append(prefix);
         }
 
         result.append('=');
@@ skipping 251 matching lines @@
     if (!node->isElementNode() || shouldSelfClose(node) || (!node->hasChildNodes() && elementCannotHaveEndTag(node)))
         return;
 
     result.append('<');
     result.append('/');
     result.append(toElement(node)->nodeNamePreservingCase());
     result.append('>');
 }
 
 }