[oilpan] Handlify childrenChanged.

Source/core/html/HTMLOutputElement.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 44 matching lines @@
     virtual void accept(Visitor*) const OVERRIDE;
 
 private:
     HTMLOutputElement(const QualifiedName&, Handle<Document>, const Handle<HTMLFormElement>&);
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual const AtomicString& formControlType() const;
     virtual bool isEnumeratable() const { return true; }
     virtual bool supportLabels() const OVERRIDE { return true; }
     virtual bool supportsFocus() const;
-    virtual void childrenChanged(bool createdByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0);
+    virtual void childrenChanged(bool createdByParser = false, const Handle<Node>& beforeChange = nullptr, const Handle<Node>& afterChange = nullptr, int childCountDelta = 0);
     virtual void reset();
 
     void setTextContentInternal(const String&);
 
     bool m_isDefaultValueMode;
     bool m_isSetTextContentInProgress;
     String m_defaultValue;
     RefPtr<DOMSettableTokenList> m_tokens;
 };
 
 } // namespace
 
 #endif