Port ParentNode API to ElementTraversal

Source/core/dom/ElementTraversal.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, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 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 14 matching lines @@
 #ifndef ElementTraversal_h
 #define ElementTraversal_h
 
 #include "core/dom/Element.h"
 #include "core/dom/NodeTraversal.h"
 
 namespace WebCore {
 
 namespace ElementTraversal {
 
-// First element child of the node.
+// First / Last element child of the node.
 Element* firstWithin(const Node&);
 Element* firstWithin(const ContainerNode&);
+Element* lastWithin(const Node&);
+Element* lastWithin(const ContainerNode&);
 
 // Pre-order traversal skipping non-element nodes.
 Element* next(const Node&);
 Element* next(const Node&, const Node* stayWithin);
 Element* next(const ContainerNode&);
 Element* next(const ContainerNode&, const Node* stayWithin);
 
 // Like next, but skips children.
 Element* nextSkippingChildren(const Node&);
 Element* nextSkippingChildren(const Node&, const Node* stayWithin);
@@ skipping 17 matching lines @@
     // Except for the root containers, only elements can have element children.
     Node* node = current.firstChild();
     while (node && !node->isElementNode())
         node = node->nextSibling();
     return toElement(node);
 }
 inline Element* firstWithin(const ContainerNode& current) { return firstElementWithinTemplate(current); }
 inline Element* firstWithin(const Node& current) { return firstElementWithinTemplate(current); }
 
 template <class NodeType>
+inline Element* lastWithinTemplate(NodeType& current)
+{
+    Node* node = current.lastChild();
+    while (node && !node->isElementNode())
+        node = node->previousSibling();
+    return toElement(node);
+}
+inline Element* lastWithin(const ContainerNode& current) { return lastWithinTemplate(current); }
+inline Element* lastWithin(const Node& current) { return lastWithinTemplate(current); }
+
+template <class NodeType>
 inline Element* traverseNextElementTemplate(NodeType& current)
 {
     Node* node = NodeTraversal::next(current);
     while (node && !node->isElementNode())
         node = NodeTraversal::nextSkippingChildren(*node);
     return toElement(node);
 }
 inline Element* next(const ContainerNode& current) { return traverseNextElementTemplate(current); }
 inline Element* next(const Node& current) { return traverseNextElementTemplate(current); }
 
@@ skipping 68 matching lines @@
     while (node && !node->isElementNode())
         node = node->nextSibling();
     return toElement(node);
 }
 
 }
 
 }
 
 #endif