Keeping track of descendants that draw content instead of recalcualting

cc/layers/surface_layer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/surface_layer.h"
 
 #include "cc/layers/surface_layer_impl.h"
 
 namespace cc {
 
 scoped_refptr<SurfaceLayer> SurfaceLayer::Create() {
   return make_scoped_refptr(new SurfaceLayer);
 }
 
 SurfaceLayer::SurfaceLayer() : Layer() {
 }
 
 SurfaceLayer::~SurfaceLayer() {}
 
 void SurfaceLayer::SetSurfaceId(SurfaceId surface_id) {
   surface_id_ = surface_id;
+  UpdateDrawsContent(true);
   SetNeedsPushProperties();
 }
 
 scoped_ptr<LayerImpl> SurfaceLayer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
   return SurfaceLayerImpl::Create(tree_impl, id()).PassAs<LayerImpl>();
 }
 
-bool SurfaceLayer::DrawsContent() const {
-  return !surface_id_.is_null() && Layer::DrawsContent();
+void SurfaceLayer::UpdateDrawsContent(bool draws_content) {
+  return Layer::UpdateDrawsContent(draws_content && !surface_id_.is_null());
 }
 
 void SurfaceLayer::PushPropertiesTo(LayerImpl* layer) {
   Layer::PushPropertiesTo(layer);
   SurfaceLayerImpl* layer_impl = static_cast<SurfaceLayerImpl*>(layer);
 
   layer_impl->SetSurfaceId(surface_id_);
 }
 
 }  // namespace cc