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

cc/layers/tiled_layer.cc

Index: cc/layers/tiled_layer.cc
diff --git a/cc/layers/tiled_layer.cc b/cc/layers/tiled_layer.cc
index 51bf212da3df826dc8ed1ea6dc45f2f27446df49..25074700f95231fb760bb4fea087fd730e27ef09 100644
--- a/cc/layers/tiled_layer.cc
+++ b/cc/layers/tiled_layer.cc
@@ -158,7 +158,9 @@ void TiledLayer::UpdateBounds() {
     InvalidateContentRect(new_rects.rect());
 }
 
-void TiledLayer::SetTileSize(gfx::Size size) { tiler_->SetTileSize(size); }
+void TiledLayer::SetTileSize(const gfx::Size& size) {
+  tiler_->SetTileSize(size);
+}
 
 void TiledLayer::SetBorderTexelOption(
     LayerTilingData::BorderTexelOption border_texel_option) {