Make collection caching code more consistent

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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "config.h"
 #include "core/html/HTMLFieldSetElement.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/ElementTraversal.h"
+#include "core/dom/NodeListsNodeData.h"
 #include "core/html/HTMLCollection.h"
 #include "core/html/HTMLFormControlsCollection.h"
 #include "core/html/HTMLLegendElement.h"
 #include "core/html/HTMLObjectElement.h"
 #include "core/rendering/RenderFieldset.h"
 #include "wtf/StdLibExtras.h"
 
 namespace blink {
 
 using namespace HTMLNames;
@@ skipping 56 matching lines @@
     return new RenderFieldset(this);
 }
 
 HTMLLegendElement* HTMLFieldSetElement::legend() const
 {
     return Traversal<HTMLLegendElement>::firstChild(*this);
 }
 
 PassRefPtrWillBeRawPtr<HTMLFormControlsCollection> HTMLFieldSetElement::elements()
 {
-    return toHTMLFormControlsCollection(ensureCachedHTMLCollection(FormControls).get());
+    return ensureCachedCollection<HTMLFormControlsCollection>(FormControls);
 }
 
 void HTMLFieldSetElement::refreshElementsIfNeeded() const
 {
     uint64_t docVersion = document().domTreeVersion();
     if (m_documentVersion == docVersion)
         return;
 
     m_documentVersion = docVersion;
 
@@ skipping 12 matching lines @@
     }
 }
 
 const FormAssociatedElement::List& HTMLFieldSetElement::associatedElements() const
 {
     refreshElementsIfNeeded();
     return m_associatedElements;
 }
 
 } // namespace