Implement ParentNode IDL interface

Source/core/html/HTMLElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Motorola Mobility. All rights reserved.
  *
  * 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 708 matching lines @@
 
     // Default on the root element is translate=yes.
     return true;
 }
 
 void HTMLElement::setTranslate(bool enable)
 {
     setAttribute(translateAttr, enable ? "yes" : "no");
 }
 
-
-PassRefPtr<HTMLCollection> HTMLElement::children()
-{
-    return ensureCachedHTMLCollection(NodeChildren);
-}
-
 bool HTMLElement::rendererIsNeeded(const NodeRenderingContext& context)
 {
     if (hasLocalName(noscriptTag)) {
         Frame* frame = document()->frame();
         if (frame && frame->script()->canExecuteScripts(NotAboutToExecuteScript))
             return false;
     } else if (hasLocalName(noembedTag)) {
         Frame* frame = document()->frame();
         if (frame && frame->loader()->subframeLoader()->allowPlugins(NotAboutToInstantiatePlugin))
             return false;
@@ skipping 300 matching lines @@
 #ifndef NDEBUG
 
 // For use in the debugger
 void dumpInnerHTML(WebCore::HTMLElement*);
 
 void dumpInnerHTML(WebCore::HTMLElement* element)
 {
     printf("%s\n", element->innerHTML().ascii().data());
 }
 #endif