Add test without skipWaiting() to demonstrate extension & service worker update.

chrome/test/data/extensions/api_test/service_worker/update_without_skip_waiting/v2/page.js

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var expectUpdate = false;
+
+var registerServiceWorkerPromise = new Promise(function(resolve, reject) {
+  expectUpdate = window.location.hash == '#expect_update';
+  var serviceWorkerRegistration;
+  navigator.serviceWorker.register('sw.js').then(function() {
+    return navigator.serviceWorker.ready;
+  }).then(function(registration) {
+    serviceWorkerRegistration = registration;
+
+    var promises = [registration.update()];
+    if (expectUpdate) {
+      promises.push(new Promise(function(resolve) {
+        registration.onupdatefound = function(e) {
+          resolve();
+        };
+      }));
+    }
+
+    return Promise.all(promises);
+  }).then(function() {
+    var installingWorker = serviceWorkerRegistration.installing;
+    if (installingWorker) {
+      // If there's an installing worker, wait for waiting worker to exist
+      // first.
+      installingWorker.onstatechange = function(e) {
+        if (installingWorker.state == 'installed') {
+          chrome.test.assertTrue(null != serviceWorkerRegistration.waiting);

[Devlin, 2015/12/10 18:16:57]

prefer chrome.test.assertTrue(!!serviceWorkerRegistration.waiting)

[lazyboy, 2015/12/10 18:59:44]

Done.

+          resolve(serviceWorkerRegistration.active);
+        }
+      }
+    } else {
+      chrome.test.assertFalse(expectUpdate);
+      chrome.test.assertEq(null, serviceWorkerRegistration.waiting);
+      resolve(serviceWorkerRegistration.active);
+    }
+  }).catch(function(err) {
+    reject(err);
+  });
+});
+
+registerServiceWorkerPromise.then(function(serviceWorker) {
+  var channel = new MessageChannel();
+  channel.port1.onmessage = function(e) {
+    chrome.test.log('Message received from SW: ' + e.data);
+    var response = e.data;
+    if (expectUpdate)
+      response += ' (with update)';
+    chrome.test.sendMessage(response);
+  };
+  serviceWorker.postMessage('ping', [channel.port2]);
+}).catch(function(err) {
+  chrome.test.log(err);
+  chrome.test.sendMessage('FAILURE_V2');
+});