[#6]Pass gfx structs by const ref (gfx::Vector2d)

cc/test/tiled_layer_test_common.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TEST_TILED_LAYER_TEST_COMMON_H_
 #define CC_TEST_TILED_LAYER_TEST_COMMON_H_
 
 #include "cc/base/region.h"
 #include "cc/layers/tiled_layer.h"
 #include "cc/layers/tiled_layer_impl.h"
@@ skipping 12 matching lines @@
 class FakeLayerUpdater : public LayerUpdater {
  public:
   class Resource : public LayerUpdater::Resource {
    public:
     Resource(FakeLayerUpdater* updater,
              scoped_ptr<PrioritizedResource> resource);
     virtual ~Resource();
 
     virtual void Update(ResourceUpdateQueue* queue,
                         const gfx::Rect& source_rect,
-                        gfx::Vector2d dest_offset,
+                        const gfx::Vector2d& dest_offset,
                         bool partial_update) OVERRIDE;
 
    private:
     FakeLayerUpdater* layer_;
     SkBitmap bitmap_;
 
     DISALLOW_COPY_AND_ASSIGN(Resource);
   };
 
   FakeLayerUpdater();
@@ skipping 108 matching lines @@
   virtual ~FakeTiledLayerWithScaledBounds();
   gfx::Size forced_content_bounds_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FakeTiledLayerWithScaledBounds);
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_TILED_LAYER_TEST_COMMON_H_