cc: Replace render surface layer list with a render surface list

cc/layers/layer_collections.h

Index: cc/layers/layer_collections.h
diff --git a/cc/layers/layer_collections.h b/cc/layers/layer_collections.h
index c7a2b7462059be23ad5022e0fd4623feef5ac6a7..14da9699d14ec378863ada47976edcd23274f1b3 100644
--- a/cc/layers/layer_collections.h
+++ b/cc/layers/layer_collections.h
@@ -15,10 +15,12 @@
 namespace cc {
 class Layer;
 class LayerImpl;
+class RenderSurfaceImpl;
 
 using LayerList = std::vector<scoped_refptr<Layer>>;
 using OwnedLayerImplList = std::vector<std::unique_ptr<LayerImpl>>;
 using LayerImplList = std::vector<LayerImpl*>;
+using RenderSurfaceList = std::vector<RenderSurfaceImpl*>;
 using OwnedLayerImplMap = std::unordered_map<int, std::unique_ptr<LayerImpl>>;
 using LayerImplMap = std::unordered_map<int, LayerImpl*>;