[oilpan] Completely move HTMLFormControlElement's hierarchy to the managed heap

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 21 matching lines @@
 #define HTMLOutputElement_h
 
 #include "core/html/DOMSettableTokenList.h"
 #include "core/html/HTMLFormControlElement.h"
 #include <wtf/OwnPtr.h>
 
 namespace WebCore {
 
 class HTMLOutputElement : public HTMLFormControlElement {
 public:
-    static PassRefPtr<HTMLOutputElement> create(const QualifiedName&, Document*, HTMLFormElement*);
+    static Result<HTMLOutputElement> create(const QualifiedName&, Document*, HTMLFormElement*);
 
     virtual bool willValidate() const { return false; }
 
     String value() const;
     void setValue(const String&);
     String defaultValue() const;
     void setDefaultValue(const String&);
     void setFor(const String&);
     DOMSettableTokenList* htmlFor() const;
     
     virtual bool canContainRangeEndPoint() const { return false; }
 
+    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
+
 private:
     HTMLOutputElement(const QualifiedName&, Document*, 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 reset();
 
     void setTextContentInternal(const String&);
 
     bool m_isDefaultValueMode;
     bool m_isSetTextContentInProgress;
     String m_defaultValue;
     RefPtr<DOMSettableTokenList> m_tokens;
 };
 
 } // namespace
 
 #endif