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

Source/core/dom/DocumentStyleSheetCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 30 matching lines @@
 #include "core/page/Settings.h"
 #include "core/svg/SVGStyleElement.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 DocumentStyleSheetCollection::DocumentStyleSheetCollection(TreeScope* treeScope)
     : StyleSheetCollection(treeScope)
 {
-    ASSERT(treeScope->rootNode() == treeScope->rootNode()->document());
+    ASSERT(treeScope->rootNode() == &treeScope->rootNode()->document());
 }
 
 void DocumentStyleSheetCollection::collectStyleSheets(StyleSheetCollections* collections, Vector<RefPtr<StyleSheet> >& styleSheets, Vector<RefPtr<CSSStyleSheet> >& activeSheets)
 {
     if (document()->settings() && !document()->settings()->authorAndUserStylesEnabled())
         return;
 
     DocumentOrderedList::iterator begin = m_styleSheetCandidateNodes.begin();
     DocumentOrderedList::iterator end = m_styleSheetCandidateNodes.end();
     for (DocumentOrderedList::iterator it = begin; it != end; ++it) {
@@ skipping 74 matching lines @@
         if (activeSheet)
             activeSheets.append(activeSheet);
     }
 }
 
 static void collectActiveCSSStyleSheetsFromSeamlessParents(Vector<RefPtr<CSSStyleSheet> >& sheets, Document* document)
 {
     HTMLIFrameElement* seamlessParentIFrame = document->seamlessParentIFrame();
     if (!seamlessParentIFrame)
         return;
-    sheets.append(seamlessParentIFrame->document()->styleSheetCollections()->activeAuthorStyleSheets());
+    sheets.append(seamlessParentIFrame->document().styleSheetCollections()->activeAuthorStyleSheets());
 }
 
 bool DocumentStyleSheetCollection::updateActiveStyleSheets(StyleSheetCollections* collections, StyleResolverUpdateMode updateMode)
 {
     Vector<RefPtr<StyleSheet> > styleSheets;
     Vector<RefPtr<CSSStyleSheet> > activeCSSStyleSheets;
     activeCSSStyleSheets.append(collections->injectedAuthorStyleSheets());
     activeCSSStyleSheets.append(collections->documentAuthorStyleSheets());
     collectActiveCSSStyleSheetsFromSeamlessParents(activeCSSStyleSheets, document());
     collectStyleSheets(collections, styleSheets, activeCSSStyleSheets);
@@ skipping 20 matching lines @@
     }
     m_scopingNodesForStyleScoped.didRemoveScopingNodes();
     m_activeAuthorStyleSheets.swap(activeCSSStyleSheets);
     m_styleSheetsForStyleSheetList.swap(styleSheets);
     updateUsesRemUnits();
 
     return requiresFullStyleRecalc;
 }
 
 }