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

cc/resources/picture_layer_tiling_set_unittest.cc

Index: cc/resources/picture_layer_tiling_set_unittest.cc
diff --git a/cc/resources/picture_layer_tiling_set_unittest.cc b/cc/resources/picture_layer_tiling_set_unittest.cc
index 96129c64fe5452aa0fc260c12cd4b7e1df728868..3939f09c0f3068f91e0b45ad1e46c7fcccae9c70 100644
--- a/cc/resources/picture_layer_tiling_set_unittest.cc
+++ b/cc/resources/picture_layer_tiling_set_unittest.cc
@@ -157,7 +157,7 @@ class PictureLayerTilingSetSyncTest : public testing::Test {
   }
 
   // Sync from source to target.
-  void SyncTilings(gfx::Size new_bounds,
+  void SyncTilings(const gfx::Size& new_bounds,
                    const Region& invalidation,
                    float minimum_scale) {
     for (size_t i = 0; i < source_->num_tilings(); ++i)
@@ -168,19 +168,19 @@ class PictureLayerTilingSetSyncTest : public testing::Test {
     target_->SyncTilings(
         *source_.get(), new_bounds, invalidation, minimum_scale);
   }
-  void SyncTilings(gfx::Size new_bounds) {
+  void SyncTilings(const gfx::Size& new_bounds) {
     Region invalidation;
     SyncTilings(new_bounds, invalidation, 0.f);
   }
-  void SyncTilings(gfx::Size new_bounds, const Region& invalidation) {
+  void SyncTilings(const gfx::Size& new_bounds, const Region& invalidation) {
     SyncTilings(new_bounds, invalidation, 0.f);
   }
-  void SyncTilings(gfx::Size new_bounds, float minimum_scale) {
+  void SyncTilings(const gfx::Size& new_bounds, float minimum_scale) {
     Region invalidation;
     SyncTilings(new_bounds, invalidation, minimum_scale);
   }
 
-  void VerifyTargetEqualsSource(gfx::Size new_bounds) const {
+  void VerifyTargetEqualsSource(const gfx::Size& new_bounds) const {
     ASSERT_FALSE(new_bounds.IsEmpty());
     EXPECT_EQ(target_->num_tilings(), source_->num_tilings());
     EXPECT_EQ(target_->layer_bounds().ToString(), new_bounds.ToString());