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

cc/test/pixel_test_output_surface.cc

 // 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 "cc/test/pixel_test_output_surface.h"
 
 #include "cc/output/output_surface_client.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 
 PixelTestOutputSurface::PixelTestOutputSurface(
     scoped_refptr<ContextProvider> context_provider)
     : OutputSurface(context_provider), external_stencil_test_(false) {}
 
 PixelTestOutputSurface::PixelTestOutputSurface(
     scoped_ptr<SoftwareOutputDevice> software_device)
     : OutputSurface(software_device.Pass()), external_stencil_test_(false) {}
 
-void PixelTestOutputSurface::Reshape(gfx::Size size, float scale_factor) {
+void PixelTestOutputSurface::Reshape(const gfx::Size& size,
+                                     float scale_factor) {
   gfx::Size expanded_size(size.width() + surface_expansion_size_.width(),
                           size.height() + surface_expansion_size_.height());
   OutputSurface::Reshape(expanded_size, scale_factor);
 }
 
 bool PixelTestOutputSurface::HasExternalStencilTest() const {
   return external_stencil_test_;
 }
 
 }  // namespace cc