Move Node/ContainerNode's traverseToChildAt() to NodeTraversal

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 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
  * License as published by the Free Software Foundation; either
@@ skipping 448 matching lines @@
     bool inDocument() const
     {
         return getFlag(InDocumentFlag);
     }
     bool isInShadowTree() const { return getFlag(IsInShadowTreeFlag); }
     bool isInTreeScope() const { return getFlag(static_cast<NodeFlags>(InDocumentFlag | IsInShadowTreeFlag)); }
 
     bool isDocumentTypeNode() const { return nodeType() == DOCUMENT_TYPE_NODE; }
     virtual bool childTypeAllowed(NodeType) const { return false; }
     unsigned countChildren() const;
-    Node* traverseToChildAt(unsigned index) const;
 
     bool isDescendantOf(const Node*) const;
     bool contains(const Node*) const;
     bool containsIncludingShadowDOM(const Node*) const;
     bool containsIncludingHostElements(const Node&) const;
     Node* commonAncestor(const Node&, Node* (*parent)(const Node&));
 
     // Used to determine whether range offsets use characters or node indices.
     virtual bool offsetInCharacters() const;
     // Number of DOM 16-bit units contained in node. Note that rendered text length can be different - e.g. because of
@@ skipping 401 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif