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