[#7] Pass gfx structs by const ref (gfx::Size)

cc/test/layer_tree_pixel_test.h

 // Copyright 2013 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.
 
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/resources/single_release_callback.h"
@@ skipping 57 matching lines @@
   void RunPixelTest(PixelTestType type,
                     scoped_refptr<Layer> content_root,
                     base::FilePath file_name);
 
   void RunPixelTestWithReadbackTarget(PixelTestType type,
                                       scoped_refptr<Layer> content_root,
                                       Layer* target,
                                       base::FilePath file_name);
 
   scoped_ptr<SkBitmap> CopyTextureMailboxToBitmap(
-      gfx::Size size,
+      const gfx::Size& size,
       const TextureMailbox& texture_mailbox);
 
   void CopyBitmapToTextureMailboxAsTexture(
       const SkBitmap& bitmap,
       TextureMailbox* texture_mailbox,
       scoped_ptr<SingleReleaseCallback>* release_callback);
 
   void ReleaseTextureMailbox(scoped_ptr<gpu::GLInProcessContext> context,
                              uint32 texture,
                              uint32 sync_point,
@@ skipping 13 matching lines @@
   base::FilePath ref_file_;
   scoped_ptr<SkBitmap> result_bitmap_;
   std::vector<scoped_refptr<TextureLayer> > texture_layers_;
   int pending_texture_mailbox_callbacks_;
   bool impl_side_painting_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_LAYER_TREE_PIXEL_TEST_H_