feat(aio): enable activating available ServiceWorker updates (#15561)

aio/src/testing/sw-update-notifications.service.ts

@@ -0,0 +1,4 @@
+export class MockSwUpdateNotificationsService {
+  enable = jasmine.createSpy('MockSwUpdateNotificationsService.enable');
+  disable = jasmine.createSpy('MockSwUpdateNotificationsService.disable');
+}

aio/src/testing/sw-updates.service.ts

@@ -0,0 +1,20 @@
+import { Subject } from 'rxjs/Subject';
+import 'rxjs/add/operator/distinctUntilChanged';
+import 'rxjs/add/operator/take';
+
+
+export class MockSwUpdatesService {
+  $$activateUpdateSubj = new Subject<boolean>();
+  $$isUpdateAvailableSubj = new Subject<boolean>();
+  isUpdateAvailable = this.$$isUpdateAvailableSubj.distinctUntilChanged();
+
+  activateUpdate(): Promise<boolean> {
+    return new Promise(resolve => {
+      this.$$activateUpdateSubj
+          // Better simulate what actually happens with the real ServiceWorker.
+          .take(1)
+          .do(() => this.$$isUpdateAvailableSubj.next(false))
+          .subscribe(resolve);
+    });
+  }
+}