cc : Stop pushing layers from hidden subtrees at commit

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index e826e2d93900d0e34f10261a4e00b6ac885ad6fc..3dbb439a2d9c4f54d2f7faa33496bf5bfa881950 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1094,6 +1094,22 @@ bool LayerTreeHost::PaintContent(const LayerList& update_layer_list,
   return did_paint_content;
 }
 
+void LayerTreeHost::AddHiddenSurfaceLayerId(Layer* layer) {
+  DCHECK(layer->is_hidden());
+  const SurfaceId* surface_id = layer->GetSurfaceId();
+  if (surface_id)
+    hidden_surface_layer_ids_.push_back(surface_id);
+}
+
+using SurfaceIdsList = std::vector<const SurfaceId*>;
+const SurfaceIdsList* LayerTreeHost::HiddenSurfaceLayerIds() const {
+  return &hidden_surface_layer_ids_;
+}
+
+void LayerTreeHost::ClearHiddenSurfaceLayerIds() {
+  hidden_surface_layer_ids_.clear();
+}
+
 void LayerTreeHost::AddLayerShouldPushProperties(Layer* layer) {
   layers_that_should_push_properties_.insert(layer);
 }