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

Source/core/page/TouchDisambiguation.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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 33 matching lines @@
 #include "core/page/FrameView.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderBlock.h"
 
 using namespace std;
 
 namespace WebCore {
 
 static IntRect boundingBoxForEventNodes(Node* eventNode)
 {
-    if (!eventNode->document()->view())
+    if (!eventNode->document().view())
         return IntRect();
 
     IntRect result;
     Node* node = eventNode;
     while (node) {
         // Skip the whole sub-tree if the node doesn't propagate events.
         if (node != eventNode && node->willRespondToMouseClickEvents()) {
             node = NodeTraversal::nextSkippingChildren(node, eventNode);
             continue;
         }
         result.unite(node->pixelSnappedBoundingBox());
         node = NodeTraversal::next(node, eventNode);
     }
-    return eventNode->document()->view()->contentsToWindow(result);
+    return eventNode->document().view()->contentsToWindow(result);
 }
 
 static float scoreTouchTarget(IntPoint touchPoint, int padding, IntRect boundingBox)
 {
     if (boundingBox.isEmpty())
         return 0;
 
     float reciprocalPadding = 1.f / padding;
     float score = 1;
 
@@ skipping 62 matching lines @@
     for (HashMap<Node*, TouchTargetData>::iterator it = touchTargets.begin(); it != touchTargets.end(); ++it) {
         // Currently the scoring function uses the overlap area with the fat point as the score.
         // We ignore the candidates that has less than 1/2 overlap (we consider not really ambiguous enough) than the best candidate to avoid excessive popups.
         if (it->value.score < bestScore * 0.5)
             continue;
         goodTargets.append(it->value.windowBoundingBox);
     }
 }
 
 } // namespace WebCore