feat(i18n): provide LOCALE_ID and NgLocalization

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

@@ -10,6 +10,7 @@ import {ApplicationInitStatus} from './application_init';
 import {ApplicationRef, ApplicationRef_} from './application_ref';
 import {APP_ID_RANDOM_PROVIDER} from './application_tokens';
 import {IterableDiffers, KeyValueDiffers, defaultIterableDiffers, defaultKeyValueDiffers} from './change_detection/change_detection';
+import {LOCALE_ID} from './i18n/tokens';
 import {Compiler} from './linker/compiler';
 import {ComponentResolver} from './linker/component_resolver';
 import {DynamicComponentLoader, DynamicComponentLoader_} from './linker/dynamic_component_loader';
@@ -51,6 +52,7 @@ export const APPLICATION_COMMON_PROVIDERS: Array<Type<any>|{[k: string]: any}|an
     {provide: IterableDiffers, useFactory: _iterableDiffersFactory},
     {provide: KeyValueDiffers, useFactory: _keyValueDiffersFactory},
     {provide: DynamicComponentLoader, useClass: DynamicComponentLoader_},
+    {provide: LOCALE_ID, useValue: 'en_US'},
   ]
 })
 export class ApplicationModule {

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

@@ -0,0 +1,17 @@
+/**
+ * @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 {LOCALE_ID} from '@angular/core';
+import {beforeEach, beforeEachProviders, ddescribe, describe, expect, iit, inject, it, xdescribe, xit} from '../testing/testing_internal';
+
+export function main() {
+  describe('Application module', () => {
+    it('should set the default locale to "en_US"',
+       inject([LOCALE_ID], (defaultLocale: string) => { expect(defaultLocale).toEqual('en_US'); }));
+  });
+}