Update cc effect node documentation.

cc/layers/render_surface_impl.cc

Index: cc/layers/render_surface_impl.cc
diff --git a/cc/layers/render_surface_impl.cc b/cc/layers/render_surface_impl.cc
index eba8543beccce7560c21c79ecb772ad3d5282bcd..e1330f14f8a4eeaad0c737c83bd5f0872296fff7 100644
--- a/cc/layers/render_surface_impl.cc
+++ b/cc/layers/render_surface_impl.cc
@@ -127,7 +127,7 @@ LayerImpl* RenderSurfaceImpl::MaskLayer() {
 }
 
 bool RenderSurfaceImpl::HasMask() const {
-  return OwningEffectNode()->mask_layer_id != EffectTree::kInvalidNodeId;
+  return OwningEffectNode()->mask_layer_id != Layer::INVALID_ID;
 }
 
 const FilterOperations& RenderSurfaceImpl::Filters() const {