Consistently use ElementTraversal API when looking for an Element

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 2453 matching lines @@
 
 void Node::unregisterScopedHTMLStyleChild()
 {
     ASSERT(hasScopedHTMLStyleChild());
     setHasScopedHTMLStyleChild(numberOfScopedHTMLStyleChildren());
 }
 
 size_t Node::numberOfScopedHTMLStyleChildren() const
 {
     size_t count = 0;
-    for (Node* child = firstChild(); child; child = child->nextSibling()) {
+    for (Element* child = ElementTraversal::firstWithin(*this); child; child = ElementTraversal::nextSibling(*child)) {
         if (child->hasTagName(HTMLNames::styleTag) && toHTMLStyleElement(child)->isRegisteredAsScoped())
-            count++;
+            ++count;
     }
 
     return count;
 }
 
 void Node::setFocus(bool flag)
 {
     document().userActionElements().setFocused(this, flag);
 }
 
@@ skipping 67 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif