Add two instrumentation tests for Web Notifications on Android.

chrome/test/data/notifications/notification_test_utils.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.
+
+// Returns a promise that will be resolved with an activated Service
+// Worker, or rejects when the Service Worker could not be started. There
+// will be a message port to and from the worker in |messagePort|.
+function GetActivatedServiceWorker(script, scope) {
+  return navigator.serviceWorker.getRegistration(scope)
+      .then(function(registration) {
+        // Unregister any existing Service Worker.
+        if (registration)
+          return registration.unregister();
+      }).then(function() {
+        // Register the Service Worker again.
+        return navigator.serviceWorker.register(script, { scope: scope });
+      }).then(function(registration) {
+        if (registration.active) {
+          return registration;
+        } else if (registration.waiting || registration.installing) {
+          var worker = registration.waiting || registration.installing;
+          return new Promise(function(resolve) {
+            worker.addEventListener('statechange', function () {
+              if (worker.state === 'activated')
+                resolve(registration);
+            });
+          });
+        } else {
+          return Promise.reject('Service Worker in invalid state.');
+        }
+      }).then(function(registration) {
+        return new Promise(function(resolve) {
+          var channel = new MessageChannel();
+          channel.port1.addEventListener('message', function(event) {
+            if (event.data == 'ready')
+              resolve(registration);
+          });
+
+          registration.active.postMessage(channel.port2,
+                                          [ channel.port2 ]);
+
+          messagePort = channel.port1;
+          messagePort.start();
+        });
+      });
+}