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/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()
       ]
     };
   }