examples/output-layers: fix layers not included in commit

wlr_output_set_layers() attaches layers to the output's pending
state, but then uses a detached wlr_output_state in
wlr_output_state_commit(). This results in layers being left out
of the committed state.

Fixes: 8e81b4bb42 ("examples: convert to new rendering API")

examples/output-layers.c

@@ -82,10 +82,13 @@ static void output_handle_frame(struct wl_listener *listener, void *data) {
 		};
 	}
 
-	wlr_output_set_layers(output->wlr_output, layers_arr.data,
-		layers_arr.size / sizeof(struct wlr_output_layer_state));
+	struct wlr_output_state output_state = {
+		.committed = WLR_OUTPUT_STATE_LAYERS,
+		.layers = layers_arr.data,
+		.layers_len = layers_arr.size / sizeof(struct wlr_output_layer_state),
+	};
 
-	if (!wlr_output_test(output->wlr_output)) {
+	if (!wlr_output_test_state(output->wlr_output, &output_state)) {
 		wlr_log(WLR_ERROR, "wlr_output_test() failed");
 		return;
 	}
@@ -93,7 +96,6 @@ static void output_handle_frame(struct wl_listener *listener, void *data) {
 	int width, height;
 	wlr_output_effective_resolution(output->wlr_output, &width, &height);
 
-	struct wlr_output_state output_state = {0};
 	struct wlr_render_pass *pass = wlr_output_begin_render_pass(output->wlr_output, &output_state,
 		NULL, NULL);