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

Source/core/html/HTMLFieldSetElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 27 matching lines @@
 using namespace HTMLNames;
 
 inline HTMLFieldSetElement::HTMLFieldSetElement(const QualifiedName& tagName, Document* document, HTMLFormElement* form)
     : HTMLFormControlElement(tagName, document, form)
     , m_documentVersion(0)
 {
     ASSERT(hasTagName(fieldsetTag));
     ScriptWrappable::init(this);
 }
 
-PassRefPtr<HTMLFieldSetElement> HTMLFieldSetElement::create(const QualifiedName& tagName, Document* document, HTMLFormElement* form)
+Result<HTMLFieldSetElement> HTMLFieldSetElement::create(const QualifiedName& tagName, Document* document, HTMLFormElement* form)
 {
-    return adoptRef(new HTMLFieldSetElement(tagName, document, form));
+    return adoptNode(new HTMLFieldSetElement(tagName, document, form));
 }
 
 void HTMLFieldSetElement::invalidateDisabledStateUnder(Element* base)
 {
     for (Element* element = ElementTraversal::firstWithin(base); element; element = ElementTraversal::next(element, base)) {
         if (element->isFormControlElement())
             static_cast<HTMLFormControlElement*>(element)->ancestorDisabledStateWasChanged();
     }
 }
 
@@ skipping 75 matching lines @@
 unsigned HTMLFieldSetElement::length() const
 {
     refreshElementsIfNeeded();
     unsigned len = 0;
     for (unsigned i = 0; i < m_associatedElements.size(); ++i)
         if (m_associatedElements[i]->isEnumeratable())
             ++len;
     return len;
 }
 
+void HTMLFieldSetElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLFormControlElement::acceptHeapVisitor(visitor);
+}
+
 } // namespace