add a new function to get a client from a wlr_surface

client.h

@@ -231,6 +231,13 @@ client_min_size(Client *c, int *width, int *height)
 	*height = state->min_height;
 }
 
+static inline Client *
+client_from_wlr_surface(struct wlr_surface *surface)
+{
+	struct wlr_scene_node *n = surface->data;
+	return n ? n->data : NULL;
+}
+
 static inline Client *
 client_from_popup(struct wlr_xdg_popup *popup)
 {