Have Node::lastDescendant() return a reference

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 365 matching lines @@
 void Node::setNodeValue(const String&)
 {
     // By default, setting nodeValue has no effect.
 }
 
 PassRefPtr<NodeList> Node::childNodes()
 {
     return ensureRareData().ensureNodeLists().ensureChildNodeList(this);
 }
 
-Node *Node::lastDescendant() const
+Node& Node::lastDescendant() const
 {
-    Node *n = const_cast<Node *>(this);
+    Node* n = const_cast<Node*>(this);
     while (n && n->lastChild())
         n = n->lastChild();
-    return n;
-}
-
-Node* Node::firstDescendant() const
-{
-    Node *n = const_cast<Node *>(this);
-    while (n && n->firstChild())
-        n = n->firstChild();
-    return n;
+    ASSERT(n);
+    return *n;
 }
 
 Node* Node::pseudoAwarePreviousSibling() const
 {
     if (parentElement() && !previousSibling()) {
         Element* parent = parentElement();
         if (isAfterPseudoElement() && parent->lastChild())
             return parent->lastChild();
         if (!isBeforePseudoElement())
             return parent->pseudoElement(BEFORE);
@@ skipping 2220 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif