Have Node::document() return a reference instead of a pointer

Source/core/svg/SVGLocatable.cpp

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Google, Inc.  All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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 47 matching lines @@
         if (isViewportElement(current))
             farthest = toSVGElement(current);
     }
     return farthest;
 }
 
 SVGRect SVGLocatable::getBBox(SVGElement* element, StyleUpdateStrategy styleUpdateStrategy)
 {
     ASSERT(element);
     if (styleUpdateStrategy == AllowStyleUpdate)
-        element->document()->updateLayoutIgnorePendingStylesheets();
+        element->document().updateLayoutIgnorePendingStylesheets();
 
     // FIXME: Eventually we should support getBBox for detached elements.
     if (!element->renderer())
         return SVGRect();
 
     return element->renderer()->objectBoundingBox();
 }
 
 AffineTransform SVGLocatable::computeCTM(SVGElement* element, CTMScope mode, StyleUpdateStrategy styleUpdateStrategy)
 {
     ASSERT(element);
     if (styleUpdateStrategy == AllowStyleUpdate)
-        element->document()->updateLayoutIgnorePendingStylesheets();
+        element->document().updateLayoutIgnorePendingStylesheets();
 
     AffineTransform ctm;
 
     SVGElement* stopAtElement = mode == NearestViewportScope ? nearestViewportElement(element) : 0;
     for (Element* currentElement = element; currentElement; currentElement = currentElement->parentOrShadowHostElement()) {
         if (!currentElement->isSVGElement())
             break;
 
         ctm = toSVGElement(currentElement)->localCoordinateSpaceTransform(mode).multiply(ctm);
 
@@ skipping 15 matching lines @@
             es.throwDOMException(InvalidStateError);
             return ctm;
         }
         ctm = targetCTM.inverse() * ctm;
     }
 
     return ctm;
 }
 
 }