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

Source/core/dom/shadow/ElementShadow.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 39 matching lines @@
 {
 }
 
 ElementShadow::~ElementShadow()
 {
     removeAllShadowRoots();
 }
 
 ShadowRoot* ElementShadow::addShadowRoot(Element* shadowHost, ShadowRoot::ShadowRootType type)
 {
-    RefPtr<ShadowRoot> shadowRoot = ShadowRoot::create(shadowHost->document(), type);
+    RefPtr<ShadowRoot> shadowRoot = ShadowRoot::create(&shadowHost->document(), type);
 
     shadowRoot->setParentOrShadowHostNode(shadowHost);
     shadowRoot->setParentTreeScope(shadowHost->treeScope());
     m_shadowRoots.push(shadowRoot.get());
     ChildNodeInsertionNotifier(shadowHost).notify(shadowRoot.get());
     setNeedsDistributionRecalc();
     shadowHost->lazyReattachIfAttached();
 
     // addShadowRoot() affects apply-author-styles. However, we know that the youngest shadow root has not had any children yet.
     // The youngest shadow root's apply-author-styles is default (false). So we can just set m_applyAuthorStyles false.
     m_applyAuthorStyles = false;
 
     InspectorInstrumentation::didPushShadowRoot(shadowHost, shadowRoot.get());
 
     return shadowRoot.get();
 }
 
 void ElementShadow::removeAllShadowRoots()
 {
     // Dont protect this ref count.
     Element* shadowHost = host();
 
     while (RefPtr<ShadowRoot> oldRoot = m_shadowRoots.head()) {
         InspectorInstrumentation::willPopShadowRoot(shadowHost, oldRoot.get());
-        shadowHost->document()->removeFocusedElementOfSubtree(oldRoot.get());
+        shadowHost->document().removeFocusedElementOfSubtree(oldRoot.get());
 
         if (oldRoot->attached())
             oldRoot->detach();
 
         m_shadowRoots.removeHead();
         oldRoot->setParentOrShadowHostNode(0);
-        oldRoot->setParentTreeScope(shadowHost->document());
+        oldRoot->setParentTreeScope(&shadowHost->document());
         oldRoot->setPrev(0);
         oldRoot->setNext(0);
         ChildNodeRemovalNotifier(shadowHost).notify(oldRoot.get());
     }
 }
 
 void ElementShadow::attach(const Node::AttachContext& context)
 {
     Node::AttachContext childrenContext(context);
     childrenContext.resolvedStyle = 0;
@@ skipping 244 matching lines @@
 
 void ElementShadow::clearDistribution()
 {
     m_nodeToInsertionPoint.clear();
 
     for (ShadowRoot* root = youngestShadowRoot(); root; root = root->olderShadowRoot())
         root->setInsertionPoint(0);
 }
 
 } // namespace