Fix some problems reported by clang static analyzer

Source/core/dom/ContainerNode.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 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 648 matching lines @@
         clone->appendChild(n->cloneNode(true), exceptionState);
 }
 
 
 bool ContainerNode::getUpperLeftCorner(FloatPoint& point) const
 {
     if (!renderer())
         return false;
     // What is this code really trying to do?
     RenderObject* o = renderer();
-    RenderObject* p = o;
 
     if (!o->isInline() || o->isReplaced()) {
         point = o->localToAbsolute(FloatPoint(), UseTransforms);
         return true;
     }
 
     // find the next text/image child, to get a position
     while (o) {
-        p = o;
+        RenderObject* p = o;
         if (o->firstChild()) {
             o = o->firstChild();
         } else if (o->nextSibling()) {
             o = o->nextSibling();
         } else {
             RenderObject* next = 0;
             while (!next && o->parent()) {
                 o = o->parent();
                 next = o->nextSibling();
             }
@@ skipping 289 matching lines @@
         return true;
 
     if (node->isElementNode() && toElement(node)->shadow())
         return true;
 
     return false;
 }
 #endif
 
 } // namespace WebCore