refactor(core): introduce `APP_BOOTSTRAP_LISTENER` multi provider

Using the `registerBootstrapListener` easily lead to race condition
and needed dependencies on `ApplicationRef`.

BREAKING CHANGE:
- `ApplicationRef.registerBootstrapListener` is deprecated. Provide a multi
  provider for the new token `APP_BOOTSTRAP_LISTENER` instead.

modules/@angular/core/index.ts

@@ -15,7 +15,7 @@ export * from './src/metadata';
 export * from './src/util';
 export * from './src/di';
 export {createPlatform, assertPlatform, disposePlatform, getPlatform, coreBootstrap, coreLoadAndBootstrap, PlatformRef, ApplicationRef, enableProdMode, lockRunMode, isDevMode, createPlatformFactory} from './src/application_ref';
-export {APP_ID, APP_INITIALIZER, PACKAGE_ROOT_URL, PLATFORM_INITIALIZER} from './src/application_tokens';
+export {APP_ID, APP_INITIALIZER, PACKAGE_ROOT_URL, PLATFORM_INITIALIZER, APP_BOOTSTRAP_LISTENER} from './src/application_tokens';
 export * from './src/zone';
 export * from './src/render';
 export * from './src/linker';

modules/@angular/core/src/application_ref.ts

@@ -11,7 +11,7 @@ import {ListWrapper} from '../src/facade/collection';
 import {BaseException, ExceptionHandler, unimplemented} from '../src/facade/exceptions';
 import {ConcreteType, Type, isBlank, isPresent, isPromise} from '../src/facade/lang';
 
-import {APP_INITIALIZER, PLATFORM_INITIALIZER} from './application_tokens';
+import {APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, PLATFORM_INITIALIZER} from './application_tokens';
 import {ChangeDetectorRef} from './change_detection/change_detector_ref';
 import {Console} from './console';
 import {Inject, Injectable, Injector, OpaqueToken, Optional, ReflectiveInjector, SkipSelf, forwardRef} from './di';
@@ -400,6 +400,9 @@ export abstract class ApplicationRef {
   /**
    * Register a listener to be called each time `bootstrap()` is called to bootstrap
    * a new root component.
+   *
+   * @deprecated Provide a callback via a multi provider for {@link APP_BOOTSTRAP_LISTENER}
+   * instead.
    */
   abstract registerBootstrapListener(listener: (ref: ComponentRef<any>) => void): void;
 
@@ -503,6 +506,9 @@ export class ApplicationRef_ extends ApplicationRef {
         this._zone.onMicrotaskEmpty, (_) => { this._zone.run(() => { this.tick(); }); });
   }
 
+  /**
+   * @deprecated
+   */
   registerBootstrapListener(listener: (ref: ComponentRef<any>) => void): void {
     this._bootstrapListeners.push(listener);
   }
@@ -564,7 +570,11 @@ export class ApplicationRef_ extends ApplicationRef {
     this._changeDetectorRefs.push(componentRef.changeDetectorRef);
     this.tick();
     this._rootComponents.push(componentRef);
-    this._bootstrapListeners.forEach((listener) => listener(componentRef));
+    // Get the listeners lazily to prevent DI cycles.
+    const listeners =
+        <((compRef: ComponentRef<any>) => void)[]>this._injector.get(APP_BOOTSTRAP_LISTENER, [])
+            .concat(this._bootstrapListeners);
+    listeners.forEach((listener) => listener(componentRef));
   }
 
   /** @internal */

modules/@angular/core/src/application_tokens.ts

@@ -53,6 +53,13 @@ export const PLATFORM_INITIALIZER: any = new OpaqueToken('Platform Initializer')
  */
 export const APP_INITIALIZER: any = new OpaqueToken('Application Initializer');
 
+/**
+ * All callbacks provided via this token will be called when a component has been bootstrapped.
+ *
+ * @experimental
+ */
+export const APP_BOOTSTRAP_LISTENER = new OpaqueToken('appBootstrapListener');
+
 /**
  * A token which indicates the root directory of the application
  * @experimental

modules/@angular/core/test/application_ref_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {APP_INITIALIZER, ChangeDetectorRef, CompilerFactory, Component, Injector, NgModule, PlatformRef} from '@angular/core';
+import {APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, ChangeDetectorRef, CompilerFactory, Component, Injector, NgModule, PlatformRef} from '@angular/core';
 import {ApplicationRef, ApplicationRef_} from '@angular/core/src/application_ref';
 import {Console} from '@angular/core/src/console';
 import {ComponentRef} from '@angular/core/src/linker/component_factory';
@@ -57,11 +57,9 @@ export function main() {
     }
 
     describe('ApplicationRef', () => {
-      var ref: ApplicationRef_;
       beforeEach(() => { TestBed.configureTestingModule({imports: [createModule()]}); });
-      beforeEach(inject([ApplicationRef], (_ref: ApplicationRef_) => { ref = _ref; }));
 
-      it('should throw when reentering tick', () => {
+      it('should throw when reentering tick', inject([ApplicationRef], (ref: ApplicationRef_) => {
            var cdRef = <any>new SpyChangeDetectorRef();
            try {
              ref.registerChangeDetector(cdRef);
@@ -70,35 +68,60 @@ export function main() {
            } finally {
              ref.unregisterChangeDetector(cdRef);
            }
-      });
+         }));
 
       describe('run', () => {
-        it('should rethrow errors even if the exceptionHandler is not rethrowing', () => {
+        it('should rethrow errors even if the exceptionHandler is not rethrowing',
+           inject([ApplicationRef], (ref: ApplicationRef_) => {
              expect(() => ref.run(() => { throw new BaseException('Test'); })).toThrowError('Test');
-        });
+           }));
 
         it('should return a promise with rejected errors even if the exceptionHandler is not rethrowing',
-           async(() => {
+           async(inject([ApplicationRef], (ref: ApplicationRef_) => {
              var promise: Promise<any> = ref.run(() => Promise.reject('Test'));
              promise.then(() => expect(false).toBe(true), (e) => { expect(e).toEqual('Test'); });
-           }));
+           })));
       });
 
       describe('registerBootstrapListener', () => {
-        it('should be called when a component is bootstrapped', () => {
+        it('should be called when a component is bootstrapped',
+           inject([ApplicationRef], (ref: ApplicationRef_) => {
              const capturedCompRefs: ComponentRef<any>[] = [];
              ref.registerBootstrapListener((compRef) => capturedCompRefs.push(compRef));
              const compRef = ref.bootstrap(SomeComponent);
              expect(capturedCompRefs).toEqual([compRef]);
+           }));
+
+        it('should be called immediately when a component was bootstrapped before',
+           inject([ApplicationRef], (ref: ApplicationRef_) => {
+             ref.registerBootstrapListener((compRef) => capturedCompRefs.push(compRef));
+             const capturedCompRefs: ComponentRef<any>[] = [];
+             const compRef = ref.bootstrap(SomeComponent);
+             expect(capturedCompRefs).toEqual([compRef]);
+           }));
       });
 
-        it('should be called immediately when a component was bootstrapped before', () => {
-          ref.registerBootstrapListener((compRef) => capturedCompRefs.push(compRef));
-          const capturedCompRefs: ComponentRef<any>[] = [];
+      describe('APP_BOOTSTRAP_LISTENER', () => {
+        let capturedCompRefs: ComponentRef<any>[];
+        beforeEach(() => {
+          capturedCompRefs = [];
+          TestBed.configureTestingModule({
+            providers: [{
+              provide: APP_BOOTSTRAP_LISTENER,
+              multi: true,
+              useValue: (compRef: any) => { capturedCompRefs.push(compRef); }
+            }]
+          });
+        });
+
+        it('should be called when a component is bootstrapped',
+           inject([ApplicationRef], (ref: ApplicationRef_) => {
              const compRef = ref.bootstrap(SomeComponent);
              expect(capturedCompRefs).toEqual([compRef]);
+           }));
+
       });
-      });
+
     });
 
     describe('bootstrapModule', () => {

modules/@angular/router/src/common_router_providers.ts

@@ -7,7 +7,7 @@
  */
 
 import {Location, LocationStrategy, PathLocationStrategy} from '@angular/common';
-import {ANALYZE_FOR_ENTRY_COMPONENTS, APP_INITIALIZER, ApplicationRef, ComponentResolver, Injector, NgModuleFactoryLoader, OpaqueToken, SystemJsNgModuleLoader} from '@angular/core';
+import {ANALYZE_FOR_ENTRY_COMPONENTS, APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, ApplicationRef, ComponentResolver, Injector, NgModuleFactoryLoader, OpaqueToken, SystemJsNgModuleLoader} from '@angular/core';
 
 import {Routes} from './config';
 import {Router} from './router';
@@ -53,12 +53,8 @@ export function rootRoute(router: Router): ActivatedRoute {
   return router.routerState.root;
 }
 
-export function setupRouterInitializer(injector: Injector) {
-  return () => {
-    injector.get(ApplicationRef).registerBootstrapListener(() => {
-      injector.get(Router).initialNavigation();
-    });
-  };
+export function initialRouterNavigation(router: Router) {
+  return () => { router.initialNavigation(); };
 }
 
 /**
@@ -102,11 +98,19 @@ export function provideRouter(routes: Routes, config: ExtraOptions = {}): any[]
     RouterOutletMap, {provide: ActivatedRoute, useFactory: rootRoute, deps: [Router]},
 
     // Trigger initial navigation
-    {provide: APP_INITIALIZER, multi: true, useFactory: setupRouterInitializer, deps: [Injector]},
-    {provide: NgModuleFactoryLoader, useClass: SystemJsNgModuleLoader}
+    provideRouterInitializer(), {provide: NgModuleFactoryLoader, useClass: SystemJsNgModuleLoader}
   ];
 }
 
+export function provideRouterInitializer() {
+  return {
+    provide: APP_BOOTSTRAP_LISTENER,
+    multi: true,
+    useFactory: initialRouterNavigation,
+    deps: [Router]
+  };
+}
+
 /**
  * Router configuration.
  *

modules/@angular/router/src/router_module.ts

@@ -9,7 +9,7 @@
 import {APP_BASE_HREF, HashLocationStrategy, Location, LocationStrategy, PathLocationStrategy, PlatformLocation} from '@angular/common';
 import {ApplicationRef, ComponentResolver, Inject, Injector, ModuleWithProviders, NgModule, NgModuleFactoryLoader, OpaqueToken, Optional, SystemJsNgModuleLoader} from '@angular/core';
 
-import {ExtraOptions, ROUTER_CONFIGURATION, provideRouterConfig, provideRoutes, rootRoute, setupRouter} from './common_router_providers';
+import {ExtraOptions, ROUTER_CONFIGURATION, provideRouterConfig, provideRouterInitializer, provideRoutes, rootRoute, setupRouter} from './common_router_providers';
 import {Routes} from './config';
 import {RouterLink, RouterLinkWithHref} from './directives/router_link';
 import {RouterLinkActive} from './directives/router_link_active';
@@ -76,13 +76,6 @@ export const ROUTER_PROVIDERS: any[] = [
  */
 @NgModule({declarations: ROUTER_DIRECTIVES, exports: ROUTER_DIRECTIVES})
 export class RouterModule {
-  constructor(private injector: Injector, appRef: ApplicationRef) {
-    // do the initialization only once
-    if ((<any>injector).parent.get(RouterModule, null)) return;
-
-    appRef.registerBootstrapListener(() => { injector.get(Router).initialNavigation(); });
-  }
-
   static forRoot(routes: Routes, config?: ExtraOptions): ModuleWithProviders {
     return {
       ngModule: RouterModule,
@@ -94,7 +87,8 @@ export class RouterModule {
           deps: [
             PlatformLocation, [new Inject(APP_BASE_HREF), new Optional()], ROUTER_CONFIGURATION
           ]
-        }
+        },
+        provideRouterInitializer()
       ]
     };
   }