backend/headless: Use output state to set init custom mode

backend/headless/output.c

@@ -120,11 +120,14 @@ struct wlr_output *wlr_headless_add_output(struct wlr_backend *wlr_backend,
 		return NULL;
 	}
 	output->backend = backend;
-	wlr_output_init(&output->wlr_output, &backend->backend, &output_impl,
-		backend->display, NULL);
 	struct wlr_output *wlr_output = &output->wlr_output;
 
-	output_set_custom_mode(output, width, height, 0);
+	struct wlr_output_state state;
+	wlr_output_state_init(&state);
+	wlr_output_state_set_custom_mode(&state, width, height, 0);
+
+	wlr_output_init(wlr_output, &backend->backend, &output_impl, backend->display, &state);
+	wlr_output_state_finish(&state);
 
 	size_t output_num = ++last_output_num;