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

Source/core/html/HTMLSourceElement.cpp

 /*
  * 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 105 matching lines @@
 {
     LOG(Media, "HTMLSourceElement::errorEventTimerFired - %p", this);
     dispatchEvent(Event::create(eventNames().errorEvent, false, true));
 }
 
 bool HTMLSourceElement::isURLAttribute(const Attribute& attribute) const
 {
     return attribute.name() == srcAttr || HTMLElement::isURLAttribute(attribute);
 }
 
+void HTMLSourceElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLElement::acceptHeapVisitor(visitor);
 }
+
+}