Reduce forward declarations in core/dom

Source/core/dom/DocumentParser.h

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2005, 2006 Apple Computer, Inc.
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2010 Google, Inc.
  *
  * 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.
@@ skipping 13 matching lines @@
 #ifndef DocumentParser_h
 #define DocumentParser_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/RefCounted.h"
 
 namespace WebCore {
 
 class Document;
-class DocumentWriter;
 class SegmentedString;
 class ScriptableDocumentParser;
 class TextResourceDecoder;
 
 class DocumentParser : public RefCountedWillBeGarbageCollectedFinalized<DocumentParser> {
 public:
     virtual ~DocumentParser();
     virtual void trace(Visitor*);
 
     virtual ScriptableDocumentParser* asScriptableDocumentParser() { return 0; }
@@ skipping 77 matching lines @@
     bool m_documentWasLoadedAsPartOfNavigation;
 
     // Every DocumentParser needs a pointer back to the document.
     // m_document will be 0 after the parser is stopped.
     RawPtrWillBeMember<Document> m_document;
 };
 
 } // namespace WebCore
 
 #endif // DocumentParser_h