Have NodeTraversal::nextSkippingChildren() take a reference

Source/core/dom/NodeTraversal.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, 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 56 matching lines @@
         return next;
     for (current = current->parentNode(); current; current = current->parentNode()) {
         if (current == stayWithin)
             return 0;
         if (Node* next = current->pseudoAwareNextSibling())
             return next;
     }
     return 0;
 }
 
-Node* nextAncestorSibling(const Node* current)
+Node* nextAncestorSibling(const Node& current)
 {
-    ASSERT(!current->nextSibling());
-    for (current = current->parentNode(); current; current = current->parentNode()) {
-        if (current->nextSibling())
-            return current->nextSibling();
+    ASSERT(!current.nextSibling());
+    for (Node* parent = current.parentNode(); parent; parent = parent->parentNode()) {
+        if (parent->nextSibling())
+            return parent->nextSibling();
     }
     return 0;
 }
 
-Node* nextAncestorSibling(const Node* current, const Node* stayWithin)
+Node* nextAncestorSibling(const Node& current, const Node* stayWithin)
 {
-    ASSERT(!current->nextSibling());
+    ASSERT(!current.nextSibling());
     ASSERT(current != stayWithin);
-    for (current = current->parentNode(); current; current = current->parentNode()) {
-        if (current == stayWithin)
+    for (Node* parent = current.parentNode(); parent; parent = parent->parentNode()) {
+        if (parent == stayWithin)
             return 0;
-        if (current->nextSibling())
-            return current->nextSibling();
+        if (parent->nextSibling())
+            return parent->nextSibling();
     }
     return 0;
 }
 
 Node* previous(const Node& current, const Node* stayWithin)
 {
     if (current == stayWithin)
         return 0;
     if (current.previousSibling()) {
         Node* previous = current.previousSibling();
@@ skipping 58 matching lines @@
 {
     if (current == stayWithin)
         return 0;
     if (current.previousSibling())
         return current.previousSibling();
     return previousAncestorSiblingPostOrder(current, stayWithin);
 }
 
 }
 }