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

cc/test/fake_picture_layer_impl.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/fake_picture_layer_impl.h"
 
 #include <vector>
 #include "cc/resources/tile.h"
 #include "cc/trees/layer_tree_impl.h"
 
@@ skipping 18 matching lines @@
       new FakePictureLayerImpl(tree_impl, id())).PassAs<LayerImpl>();
 }
 
 void FakePictureLayerImpl::AppendQuads(QuadSink* quad_sink,
                                        AppendQuadsData* append_quads_data) {
   PictureLayerImpl::AppendQuads(quad_sink, append_quads_data);
   ++append_quads_count_;
 }
 
 gfx::Size FakePictureLayerImpl::CalculateTileSize(
-    gfx::Size content_bounds) const {
+    const gfx::Size& content_bounds) const {
   if (fixed_tile_size_.IsEmpty()) {
     return PictureLayerImpl::CalculateTileSize(content_bounds);
   }
 
   return fixed_tile_size_;
 }
 
 PictureLayerTiling* FakePictureLayerImpl::HighResTiling() const {
   PictureLayerTiling* result = NULL;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
@@ skipping 67 matching lines @@
     DCHECK_EQ(tilings()->tiling_at(0)->resolution(), HIGH_RESOLUTION);
     DCHECK_EQ(tilings()->tiling_at(1)->resolution(), LOW_RESOLUTION);
     HighResTiling()->CreateAllTilesForTesting();
     LowResTiling()->CreateAllTilesForTesting();
   } else {
     DCHECK_EQ(tilings()->num_tilings(), 0u);
   }
 }
 
 }  // namespace cc