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

Source/core/page/ContextMenuController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Igalia S.L
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 54 matching lines @@
         m_menuProvider->contextMenuCleared();
     m_menuProvider = 0;
     m_hitTestResult = HitTestResult();
     m_client->clearContextMenu();
 }
 
 void ContextMenuController::documentDetached(Document* document)
 {
     if (Node* innerNode = m_hitTestResult.innerNode()) {
         // Invalidate the context menu info if its target document is detached.
-        if (innerNode->document() == document)
+        if (&innerNode->document() == document)
             clearContextMenu();
     }
 }
 
 void ContextMenuController::handleContextMenuEvent(Event* event)
 {
     m_contextMenu = createContextMenu(event);
     if (!m_contextMenu)
         return;
 
@@ skipping 17 matching lines @@
 PassOwnPtr<ContextMenu> ContextMenuController::createContextMenu(Event* event)
 {
     ASSERT(event);
 
     if (!event->isMouseEvent())
         return nullptr;
 
     MouseEvent* mouseEvent = toMouseEvent(event);
     HitTestResult result(mouseEvent->absoluteLocation());
 
-    if (Frame* frame = event->target()->toNode()->document()->frame())
+    if (Frame* frame = event->target()->toNode()->document().frame())
         result = frame->eventHandler()->hitTestResultAtPoint(mouseEvent->absoluteLocation(), HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::DisallowShadowContent);
 
     if (!result.innerNonSharedNode())
         return nullptr;
 
     m_hitTestResult = result;
 
     return adoptPtr(new ContextMenu);
 }
 
 void ContextMenuController::showContextMenu(Event* event)
 {
     m_client->showContextMenu(m_contextMenu.get());
     event->setDefaultHandled();
 }
 
 void ContextMenuController::contextMenuItemSelected(const ContextMenuItem* item)
 {
     ASSERT(item->type() == ActionType || item->type() == CheckableActionType);
 
     if (item->action() < ContextMenuItemBaseCustomTag || item->action() > ContextMenuItemLastCustomTag)
         return;
 
     ASSERT(m_menuProvider);
     m_menuProvider->contextMenuItemSelected(item);
 }
 
 } // namespace WebCore