chore(internal API): introduce an internal API for ngtools. (#13415)

modules/@angular/compiler-cli/integrationtest/ngtools_src/app.component.ts

@@ -0,0 +1,10 @@
+import {Component, ViewEncapsulation} from '@angular/core';
+
+
+@Component({
+  selector: 'app-root',
+  templateUrl: 'app.component.html',
+  styleUrls: ['app.component.css'],
+  encapsulation: ViewEncapsulation.None
+})
+export class AppComponent { }