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

Source/core/html/HTMLSourceElement.h

 /*
  * Copyright (C) 2007, 2008, 2010 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 26 matching lines @@
 
     String media() const;
     String type() const;
     void setSrc(const String&);    
     void setMedia(const String&);
     void setType(const String&);
     
     void scheduleErrorEvent();
     void cancelPendingErrorEvent();
 
+    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
+
 private:
     HTMLSourceElement(const QualifiedName&, Handle<Document>);
     
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
 
     void errorEventTimerFired(Timer<HTMLSourceElement>*);
 
     Timer<HTMLSourceElement> m_errorEventTimer;
 };
 
 } //namespace
 
 #endif