Drop [LegacyImplementedInBaseClass] from ChildNode IDL interface

Source/core/dom/Node.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, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 2531 matching lines @@
     }
 
     ASSERT(isHTMLElement() || isSVGElement());
     setFlag(CustomElement);
     setFlag(newState == Upgraded, CustomElementUpgraded);
 
     if (oldState == NotCustomElement || newState == Upgraded)
         setNeedsStyleRecalc(SubtreeStyleChange); // :unresolved has changed
 }
 
-Element* Node::previousElementSibling() const
-{
-    return ElementTraversal::previousSibling(*this);
-}
-
-Element* Node::nextElementSibling() const
-{
-    return ElementTraversal::nextSibling(*this);
-}
-
 } // namespace WebCore
 
 #ifndef NDEBUG
 
 void showTree(const WebCore::Node* node)
 {
     if (node)
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif