chromium/chrome/test/data/extensions/api_test/service_worker/worker_based_background/registration_at_startup/service_worker_background.js

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

chrome.test.sendMessage('WORKER_RUNNING');

// Attach a dummy listener for onStartup to kick off the service worker on
// every browser start, so we send "WORKER_RUNNING" message.
chrome.runtime.onStartup.addListener(() => {});