feat(build): record angular version in the dom (#13164)

modules/@angular/core/index.ts

@@ -12,5 +12,10 @@
  * Entry point for all public APIs of the core package.
  */
 export * from './src/core';
+import {Version} from './src/core';
+/**
+ * @stable
+ */
+export const VERSION = new Version('0.0.0-PLACEHOLDER');
 
 // This file only reexports content of the `src` folder. Keep it that way.

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

@@ -12,6 +12,7 @@
  * Entry point from which you should import all public core APIs.
  */
 export * from './metadata';
+export * from './version';
 export * from './util';
 export * from './di';
 export {createPlatform, assertPlatform, destroyPlatform, getPlatform, PlatformRef, ApplicationRef, enableProdMode, isDevMode, createPlatformFactory, NgProbeToken} from './application_ref';
@@ -34,4 +35,4 @@ export * from './core_private_export';
 export * from './animation/metadata';
 export {AnimationTransitionEvent} from './animation/animation_transition_event';
 export {AnimationPlayer} from './animation/animation_player';
-export {Sanitizer, SecurityContext} from './security';
+export {Sanitizer, SecurityContext} from './security';

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

@@ -0,0 +1,22 @@
+/**
+ * @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
+ */
+
+/**
+ * @whatItDoes Represents the version of Angular
+ *
+ * @stable
+ */
+export class Version {
+  constructor(public full: string) {}
+
+  get major(): string { return this.full.split('.')[0]; }
+
+  get minor(): string { return this.full.split('.')[1]; }
+
+  get patch(): string { return this.full.split('.')[2]; }
+}