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 62e9349178b687b328ee201efe00d1304ff7862c..9f685d22625c68abdce4034f39562bda8b4437cc 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1253,6 +1253,21 @@ LayerImpl* LayerTreeImpl::LayerById(int id) const {
   return iter != layer_id_map_.end() ? iter->second : nullptr;
 }
 
+using SurfaceIdsList = std::vector<const SurfaceId*>;
+void LayerTreeImpl::SetHiddenSurfaceLayerIds(
+    const SurfaceIdsList* hidden_surface_layer_ids) {
+  DCHECK(hidden_surface_layer_ids_.empty());
+  hidden_surface_layer_ids_ = *hidden_surface_layer_ids;
+}
+
+const SurfaceIdsList* LayerTreeImpl::HiddenSurfaceLayerIds() const {
+  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);
 }