docs(service-worker): improve SwRegistrationOptions docs and add example (#21842)

PR Close #21842

packages/examples/service-worker/registration-options/e2e_test/registration-options_spec.ts

@@ -0,0 +1,27 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {browser, by, element} from 'protractor';
+import {verifyNoBrowserErrors} from '../../../test-utils';
+
+describe('SW `SwRegistrationOptions` example', () => {
+  const pageUrl = '/registration-options';
+  const appElem = element(by.css('example-app'));
+
+  afterEach(verifyNoBrowserErrors);
+
+  it('not register the SW by default', () => {
+    browser.get(pageUrl);
+    expect(appElem.getText()).toBe('SW enabled: false');
+  });
+
+  it('register the SW when navigating to `?sw=true`', () => {
+    browser.get(`${pageUrl}?sw=true`);
+    expect(appElem.getText()).toBe('SW enabled: true');
+  });
+});