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

cc/test/fake_picture_pile_impl.h

Index: cc/test/fake_picture_pile_impl.h
diff --git a/cc/test/fake_picture_pile_impl.h b/cc/test/fake_picture_pile_impl.h
index 20d44e398b393006f881bd50b2336ae3942c4723..ae424bbba5af69f3caf93c000b19175ec7c66d3e 100644
--- a/cc/test/fake_picture_pile_impl.h
+++ b/cc/test/fake_picture_pile_impl.h
@@ -14,16 +14,16 @@ namespace cc {
 class FakePicturePileImpl : public PicturePileImpl {
  public:
   static scoped_refptr<FakePicturePileImpl> CreateFilledPile(
-      gfx::Size tile_size,
-      gfx::Size layer_bounds);
+      const gfx::Size& tile_size,
+      const gfx::Size& layer_bounds);
 
   static scoped_refptr<FakePicturePileImpl> CreateEmptyPile(
-      gfx::Size tile_size,
-      gfx::Size layer_bounds);
+      const gfx::Size& tile_size,
+      const gfx::Size& layer_bounds);
 
   static scoped_refptr<FakePicturePileImpl> CreatePileWithRecordedRegion(
-      gfx::Size tile_size,
-      gfx::Size layer_bounds,
+      const gfx::Size& tile_size,
+      const gfx::Size& layer_bounds,
       const Region& recorded_region);
 
   static scoped_refptr<FakePicturePileImpl> CreatePile();