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

cc/output/direct_renderer.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_OUTPUT_DIRECT_RENDERER_H_
 #define CC_OUTPUT_DIRECT_RENDERER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/containers/scoped_ptr_hash_map.h"
@@ skipping 41 matching lines @@
     gfx::Rect device_clip_rect;
 
     gfx::Transform projection_matrix;
     gfx::Transform window_matrix;
 
     ContextProvider* offscreen_context_provider;
 
     bool disable_picture_quad_image_filtering;
   };
 
-  void SetEnlargePassTextureAmountForTesting(gfx::Vector2d amount);
+  void SetEnlargePassTextureAmountForTesting(const gfx::Vector2d& amount);
 
  protected:
   DirectRenderer(RendererClient* client,
                  const LayerTreeSettings* settings,
                  OutputSurface* output_surface,
                  ResourceProvider* resource_provider);
 
   static gfx::RectF QuadVertexRect();
   static void QuadRectTransform(gfx::Transform* quad_rect_transform,
                                 const gfx::Transform& quad_transform,
@@ skipping 62 matching lines @@
 
  private:
   gfx::Vector2d enlarge_pass_texture_amount_;
 
   DISALLOW_COPY_AND_ASSIGN(DirectRenderer);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_DIRECT_RENDERER_H_