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

Source/core/html/HTMLTablePartElement.cpp

 /**
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 35 matching lines @@
     return HTMLElement::isPresentationAttribute(name);
 }
 
 void HTMLTablePartElement::collectStyleForPresentationAttribute(const QualifiedName& name, const AtomicString& value, MutableStylePropertySet* style)
 {
     if (name == bgcolorAttr)
         addHTMLColorToStyle(style, CSSPropertyBackgroundColor, value);
     else if (name == backgroundAttr) {
         String url = stripLeadingAndTrailingHTMLSpaces(value);
         if (!url.isEmpty())
-            style->setProperty(CSSProperty(CSSPropertyBackgroundImage, CSSImageValue::create(document()->completeURL(url).string())));
+            style->setProperty(CSSProperty(CSSPropertyBackgroundImage, CSSImageValue::create(document().completeURL(url).string())));
     } else if (name == valignAttr) {
         if (equalIgnoringCase(value, "top"))
             addPropertyToPresentationAttributeStyle(style, CSSPropertyVerticalAlign, CSSValueTop);
         else if (equalIgnoringCase(value, "middle"))
             addPropertyToPresentationAttributeStyle(style, CSSPropertyVerticalAlign, CSSValueMiddle);
         else if (equalIgnoringCase(value, "bottom"))
             addPropertyToPresentationAttributeStyle(style, CSSPropertyVerticalAlign, CSSValueBottom);
         else if (equalIgnoringCase(value, "baseline"))
             addPropertyToPresentationAttributeStyle(style, CSSPropertyVerticalAlign, CSSValueBaseline);
         else
@@ skipping 18 matching lines @@
 
 HTMLTableElement* HTMLTablePartElement::findParentTable() const
 {
     ContainerNode* parent = NodeRenderingTraversal::parent(this);
     while (parent && !isHTMLTableElement(parent))
         parent = NodeRenderingTraversal::parent(parent);
     return toHTMLTableElement(parent);
 }
 
 }