cc : Stop pushing layers from hidden subtrees at commit

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 175c9a4f49f218506549699fdcf7e447153ab0aa..32c5f69c685cc820f1ba6013d627aa57def25d24 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1216,6 +1216,21 @@ LayerImpl* LayerTreeImpl::LayerById(int id) const {
   return iter != layer_id_map_.end() ? iter->second : nullptr;
 }
 
+using SurfaceIdsList = std::vector<const SurfaceId*>;

[enne (OOO), 2017/05/19 22:27:05]

I think this should be SurfaceId and not SurfaceId*.  Lifetimes seem a little
bit scary here.

Also in general, I think std::vector<const SurfaceId> isn't really much longer
than SurfaceIdsList and is a lot clearer.  If you don't mind avoiding the
typedef, I'd appreciate it.

[jaydasika, 2017/05/23 00:25:14]

Done.

+void LayerTreeImpl::SetHiddenSurfaceLayerIds(
+    const SurfaceIdsList* hidden_surface_layer_ids) {

[enne (OOO), 2017/05/19 22:27:05]

Maybe pass by const ref here?

[jaydasika, 2017/05/23 00:25:14]

Done.

+  DCHECK(hidden_surface_layer_ids_.empty());
+  hidden_surface_layer_ids_ = *hidden_surface_layer_ids;
+}
+
+const SurfaceIdsList* LayerTreeImpl::HiddenSurfaceLayerIds() const {

[enne (OOO), 2017/05/19 22:27:05]

Maybe a const ref and not a pointer, if it's never going to be null?

[jaydasika, 2017/05/23 00:25:14]

Done.

+  return &hidden_surface_layer_ids_;
+}
+
+void LayerTreeImpl::ClearHiddenSurfaceLayerIds() {
+  hidden_surface_layer_ids_.clear();
+}
+
 void LayerTreeImpl::AddLayerShouldPushProperties(LayerImpl* layer) {
   layers_that_should_push_properties_.insert(layer);
 }