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

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index beb282d75fb691b094b8ae57d2b7858126035488..42338e0b8197fb17f8b9b242d9243a16c534f7e0 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -751,7 +751,7 @@ bool LayerImpl::IsActive() const {
   return layer_tree_impl_->IsActiveTree();
 }
 
-void LayerImpl::SetBounds(gfx::Size bounds) {
+void LayerImpl::SetBounds(const gfx::Size& bounds) {
   if (bounds_ == bounds)
     return;
 
@@ -996,7 +996,7 @@ void LayerImpl::SetUpdateRect(const gfx::RectF& update_rect) {
   SetNeedsPushProperties();
 }
 
-void LayerImpl::SetContentBounds(gfx::Size content_bounds) {
+void LayerImpl::SetContentBounds(const gfx::Size& content_bounds) {
   if (this->content_bounds() == content_bounds)
     return;