Clean up forward declarations and include files in Source/bindings

Source/bindings/core/v8/V8StringResource.h

 /*
  * Copyright (C) 2009 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef V8StringResource_h
 #define V8StringResource_h
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "wtf/Threading.h"
 #include "wtf/text/AtomicString.h"
-#include "wtf/text/WTFString.h"
 #include <v8.h>
 
 namespace blink {
 
-class ExternalStringVisitor;
-
 // WebCoreStringResource is a helper class for v8ExternalString. It is used
 // to manage the life-cycle of the underlying buffer of the external string.
 class WebCoreStringResourceBase {
 public:
     explicit WebCoreStringResourceBase(const String& string)
         : m_plainString(string)
     {
 #if ENABLE(ASSERT)
         m_threadId = WTF::currentThread();
 #endif
@@ skipping 261 matching lines @@
 }
 
 template<> inline String V8StringResource<TreatNullAndUndefinedAsNullString>::fallbackString() const
 {
     return String();
 }
 
 } // namespace blink
 
 #endif // V8StringResource_h