Simplify some parsing-related code

sky/engine/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 21 matching lines @@
 namespace blink {
 
 class Document;
 class SegmentedString;
 class HTMLDocumentParser;
 class TextResourceDecoder;
 
 class DocumentParser : public RefCounted<DocumentParser> {
 public:
     virtual ~DocumentParser();
-    virtual void trace(Visitor*);
 
     virtual HTMLDocumentParser* asHTMLDocumentParser() { return 0; }
 
     virtual void parse(mojo::ScopedDataPipeConsumerHandle) = 0;
     virtual bool processingData() const { return false; }
 
     // document() will return 0 after detach() is called.
     Document* document() const { ASSERT(m_document); return m_document; }
 
     bool isParsing() const { return m_state == ParsingState; }
@@ skipping 32 matching lines @@
     ParserState m_state;
 
     // Every DocumentParser needs a pointer back to the document.
     // m_document will be 0 after the parser is stopped.
     Document* m_document;
 };
 
 } // namespace blink
 
 #endif // DocumentParser_h