[oilpan] The Node hierarchy should have correct accept method chains

Source/core/html/TextDocument.h

 /*
  * Copyright (C) 2006, 2008, 2009 Apple 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 18 matching lines @@
 
 namespace WebCore {
 
 class TextDocument : public HTMLDocument {
 public:
     static PassRefPtr<TextDocument> create(Frame* frame, const KURL& url)
     {
         return adoptRef(new TextDocument(frame, url));
     }
 
+    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
+
 private:
     TextDocument(Frame*, const KURL&);
     
     virtual PassRefPtr<DocumentParser> createParser();
 };
 
 }
 
 #endif