feat(ngUpgrade): add support for AoT compiled upgrade applications

This commit introduces a new API to the ngUpgrade module, which is compatible
with AoT compilation. Primarily, it removes the dependency on reflection
over the Angular 2 metadata by introducing an API where this information
is explicitly defined, in the source code, in a way that is not lost through
AoT compilation.

This commit is a collaboration between @mhevery (who provided the original
design of the API); @gkalpak & @petebacondarwin (who implemented the
API and migrated the specs from the original ngUpgrade tests) and @alexeagle
(who provided input and review).

This commit is an starting point, there is still work to be done:

* add more documentation
* validate the API via internal projects
* align the ngUpgrade compilation of A1 directives closer to the real A1
  compiler
* add more unit tests
* consider support for async `templateUrl` A1 upgraded components

Closes #12239

modules/@angular/upgrade/test/aot/integration/testability_spec.ts

@@ -0,0 +1,71 @@
+/**
+ * @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 {NgModule, Testability, destroyPlatform} from '@angular/core';
+import {fakeAsync, tick} from '@angular/core/testing';
+import {BrowserModule} from '@angular/platform-browser';
+import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
+import {UpgradeModule} from '@angular/upgrade';
+import * as angular from '@angular/upgrade/src/angular_js';
+
+import {bootstrap, html} from '../test_helpers';
+
+export function main() {
+  describe('testability', () => {
+
+    beforeEach(() => destroyPlatform());
+    afterEach(() => destroyPlatform());
+
+    @NgModule({imports: [BrowserModule, UpgradeModule]})
+    class Ng2Module {
+      ngDoBootstrap() {}
+    }
+
+    it('should handle deferred bootstrap', fakeAsync(() => {
+         let applicationRunning = false;
+         const ng1Module = angular.module('ng1', []).run(() => { applicationRunning = true; });
+
+         const element = html('<div></div>');
+         window.name = 'NG_DEFER_BOOTSTRAP!' + window.name;
+
+         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module);
+
+         setTimeout(() => { (<any>window).angular.resumeBootstrap(); }, 100);
+
+         expect(applicationRunning).toEqual(false);
+         tick(100);
+         expect(applicationRunning).toEqual(true);
+       }));
+
+    it('should wait for ng2 testability', fakeAsync(() => {
+         const ng1Module = angular.module('ng1', []);
+         const element = html('<div></div>');
+
+         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
+
+           const ng2Testability: Testability = upgrade.injector.get(Testability);
+           ng2Testability.increasePendingRequestCount();
+           let ng2Stable = false;
+           let ng1Stable = false;
+
+           angular.getTestability(element).whenStable(() => { ng1Stable = true; });
+
+           setTimeout(() => {
+             ng2Stable = true;
+             ng2Testability.decreasePendingRequestCount();
+           }, 100);
+
+           expect(ng1Stable).toEqual(false);
+           expect(ng2Stable).toEqual(false);
+           tick(100);
+           expect(ng1Stable).toEqual(true);
+           expect(ng2Stable).toEqual(true);
+         });
+       }));
+  });
+}