+ using storage_type = std::set<struct layer>;
+ using layers_type = std::vector<uint32_t>;
+ using role_to_layer_map = std::vector<std::pair<std::string, int>>;
+ using addsurf_layer_map = std::map<int, int>;
+
+ // XXX: we also will need a layer_id to layer map, perhaps
+ // make this the primary map, and the surface_id->layer a
+ // secondary map.