Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/html/HTMLFormElement.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, 2007, 2008, 2009 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 65 matching lines @@
 }
 
 PassRefPtr<HTMLFormElement> HTMLFormElement::create(Document& document)
 {
     UseCounter::count(document, UseCounter::FormElement);
     return adoptRef(new HTMLFormElement(document));
 }
 
 HTMLFormElement::~HTMLFormElement()
 {
+#if !ENABLE(OILPAN)
+    // With Oilpan, either removedFrom is called or the document and
+    // form controller are dead as well and there is no need to remove
+    // this form element from it.
     document().formController().willDeleteForm(this);
+#endif
 }
 
 bool HTMLFormElement::rendererIsNeeded(const RenderStyle& style)
 {
     if (!m_wasDemoted)
         return HTMLElement::rendererIsNeeded(style);
 
     ContainerNode* node = parentNode();
     if (!node || !node->renderer())
         return HTMLElement::rendererIsNeeded(style);
@@ skipping 56 matching lines @@
             Vector<HTMLImageElement*> images(imageElements());
             notifyFormRemovedFromTree(images, root);
         } else {
             Vector<HTMLImageElement*> images;
             collectImageElements(insertionPoint->highestAncestorOrSelf(), images);
             notifyFormRemovedFromTree(images, root);
             collectImageElements(root, images);
             notifyFormRemovedFromTree(images, root);
         }
     }
+#if ENABLE(OILPAN)
+    document().formController().willDeleteForm(this);
+#endif
     HTMLElement::removedFrom(insertionPoint);
 }
 
 void HTMLFormElement::handleLocalEvents(Event* event)
 {
     Node* targetNode = event->target()->toNode();
     if (event->eventPhase() != Event::CAPTURING_PHASE && targetNode && targetNode != this && (event->type() == EventTypeNames::submit || event->type() == EventTypeNames::reset)) {
         event->stopPropagation();
         return;
     }
@@ skipping 589 matching lines @@
 }
 
 void HTMLFormElement::setDemoted(bool demoted)
 {
     if (demoted)
         UseCounter::count(document(), UseCounter::DemotedFormElement);
     m_wasDemoted = demoted;
 }
 
 } // namespace