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

Source/core/html/shadow/SpinButtonElement.cpp

 /*
  * Copyright (C) 2006, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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
@@ skipping 243 matching lines @@
     if (!flag)
         m_upDownState = Indeterminate;
     HTMLDivElement::setHovered(flag);
 }
 
 bool SpinButtonElement::shouldRespondToMouseEvents()
 {
     return !m_spinButtonOwner || m_spinButtonOwner->shouldSpinButtonRespondToMouseEvents();
 }
 
+void SpinButtonElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLDivElement::acceptHeapVisitor(visitor);
 }
+
+}