Make HTMLCollection / NodeList backward traversal consistent with forward one

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1835 matching lines @@
 
         // We also have to handle node removal.
         if (childCountDelta < 0 && newFirstChild == firstElementAfterInsertion && newFirstChild && (!newFirstChildStyle || !newFirstChildStyle->firstChildState()))
             newFirstChild->setNeedsStyleRecalc(SubtreeStyleChange);
     }
 
     // :last-child.  In the parser callback case, we don't have to check anything, since we were right the first time.
     // In the DOM case, we only need to do something if |afterChange| is not 0.
     if (childrenAffectedByLastChildRules() && beforeChange) {
         // Find our new last child.
-        Node* newLastChild = ElementTraversal::lastWithin(*this);
+        Node* newLastChild = ElementTraversal::lastChild(*this);
         RenderStyle* newLastChildStyle = newLastChild ? newLastChild->renderStyle() : 0;
 
         // Find the last element node going backwards from |beforeChange|
         Node* lastElementBeforeInsertion = beforeChange->isElementNode() ? beforeChange : ElementTraversal::previousSibling(*beforeChange);
         RenderStyle* lastElementBeforeInsertionStyle = lastElementBeforeInsertion ? lastElementBeforeInsertion->renderStyle() : 0;
 
         if (newLastChild != lastElementBeforeInsertion && lastElementBeforeInsertionStyle && lastElementBeforeInsertionStyle->lastChildState())
             lastElementBeforeInsertion->setNeedsStyleRecalc(SubtreeStyleChange);
 
         // We also have to handle node removal.  The parser callback case is similar to node removal as well in that we need to change the last child
@@ skipping 1486 matching lines @@
         || isHTMLObjectElement(*this)
         || isHTMLAppletElement(*this)
         || isHTMLCanvasElement(*this))
         return false;
     if (FullscreenElementStack::isActiveFullScreenElement(this))
         return false;
     return true;
 }
 
 } // namespace WebCore