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

Source/core/rendering/RenderFullScreen.cpp

 /*
  * Copyright (C) 2010 Apple 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:
  * 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
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 #include "core/dom/FullscreenElementStack.h"
 
 using namespace WebCore;
 
 class RenderFullScreenPlaceholder FINAL : public RenderBlock {
 public:
     RenderFullScreenPlaceholder(RenderFullScreen* owner)
         : RenderBlock(0)
         , m_owner(owner)
     {
-        setDocumentForAnonymous(owner->document());
+        setDocumentForAnonymous(&owner->document());
     }
 private:
     virtual bool isRenderFullScreenPlaceholder() const { return true; }
     virtual void willBeDestroyed();
     RenderFullScreen* m_owner;
 };
 
 void RenderFullScreenPlaceholder::willBeDestroyed()
 {
     m_owner->setPlaceholder(0);
@@ skipping 18 matching lines @@
 {
     if (m_placeholder) {
         remove();
         if (!m_placeholder->beingDestroyed())
             m_placeholder->destroy();
         ASSERT(!m_placeholder);
     }
 
     // RenderObjects are unretained, so notify the document (which holds a pointer to a RenderFullScreen)
     // if it's RenderFullScreen is destroyed.
-    if (document()) {
-        FullscreenElementStack* controller = FullscreenElementStack::from(document());
-        if (controller->fullScreenRenderer() == this)
-            controller->fullScreenRendererDestroyed();
-    }
+    FullscreenElementStack* controller = FullscreenElementStack::from(&document());
+    if (controller->fullScreenRenderer() == this)
+        controller->fullScreenRendererDestroyed();
 
     RenderFlexibleBox::willBeDestroyed();
 }
 
 static PassRefPtr<RenderStyle> createFullScreenStyle()
 {
     RefPtr<RenderStyle> fullscreenStyle = RenderStyle::createDefaultStyle();
 
     // Create a stacking context:
     fullscreenStyle->setZIndex(INT_MAX);
@@ skipping 63 matching lines @@
             if (child->isBox())
                 toRenderBox(child)->clearOverrideSize();
             child->remove();
             parent()->addChild(child, this);
             parent()->setNeedsLayoutAndPrefWidthsRecalc();
         }
     }
     if (placeholder())
         placeholder()->remove();
     remove();
-    FullscreenElementStack::from(document())->setFullScreenRenderer(0);
+    FullscreenElementStack::from(&document())->setFullScreenRenderer(0);
 }
 
 void RenderFullScreen::setPlaceholder(RenderBlock* placeholder)
 {
     m_placeholder = placeholder;
 }
 
 void RenderFullScreen::createPlaceholder(PassRefPtr<RenderStyle> style, const LayoutRect& frameRect)
 {
     if (style->width().isAuto())
         style->setWidth(Length(frameRect.width(), Fixed));
     if (style->height().isAuto())
         style->setHeight(Length(frameRect.height(), Fixed));
 
     if (!m_placeholder) {
         m_placeholder = new RenderFullScreenPlaceholder(this);
         m_placeholder->setStyle(style);
         if (parent()) {
             parent()->addChild(m_placeholder, this);
             parent()->setNeedsLayoutAndPrefWidthsRecalc();
         }
     } else
         m_placeholder->setStyle(style);
 }