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

Source/core/page/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 1059 matching lines @@
     }
 
     layer->updateLayerPositionsAfterLayout(renderView()->layer(), updateLayerPositionFlags(layer, inSubtreeLayout, m_doFullRepaint));
 
     endDeferredRepaints();
 
     updateCompositingLayersAfterLayout();
 
     m_layoutCount++;
 
-    if (AXObjectCache* cache = rootForThisLayout->document()->existingAXObjectCache())
+    if (AXObjectCache* cache = rootForThisLayout->document().existingAXObjectCache())
         cache->postNotification(rootForThisLayout, AXObjectCache::AXLayoutComplete, true);
     updateAnnotatedRegions();
 
     ASSERT(!rootForThisLayout->needsLayout());
 
     updateCanBlitOnScrollRecursively();
 
     if (document->hasListenerType(Document::OVERFLOWCHANGED_LISTENER))
         updateOverflowStatus(layoutWidth() < contentsWidth(), layoutHeight() < contentsHeight());
 
@@ skipping 1327 matching lines @@
     if (paintsEntireContents())
         return IntRect(IntPoint(), contentsSize());
 
     // Set our clip rect to be our contents.
     IntRect clipRect = contentsToWindow(visibleContentRect(clipToContents ? ExcludeScrollbars : IncludeScrollbars));
     if (!m_frame || !m_frame->ownerElement())
         return clipRect;
 
     // Take our owner element and get its clip rect.
     HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement();
-    FrameView* parentView = ownerElement->document()->view();
+    FrameView* parentView = ownerElement->document().view();
     if (parentView)
         clipRect.intersect(parentView->windowClipRectForFrameOwner(ownerElement, true));
     return clipRect;
 }
 
 IntRect FrameView::windowClipRectForFrameOwner(const HTMLFrameOwnerElement* ownerElement, bool clipToLayerContents) const
 {
     // The renderer can sometimes be null when style="display:none" interacts
     // with external content and plugins.
     if (!ownerElement->renderer())
@@ skipping 920 matching lines @@
 }
 
 AXObjectCache* FrameView::axObjectCache() const
 {
     if (frame() && frame()->document())
         return frame()->document()->existingAXObjectCache();
     return 0;
 }
 
 } // namespace WebCore