feat: add .ngsummary.ts files to support AOT unit tests

Design doc: https://docs.google.com/document/d/1VmTkz0EbEVSWfEEWEvQ5sXyQXSCvtMOw4t7pKU-jOwc/edit?usp=sharing

packages/compiler/src/summary_resolver.ts

@@ -5,6 +5,7 @@
  * 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 {Type} from '@angular/core';
 import {CompileTypeSummary} from './compile_metadata';
 import {CompilerInjectable} from './injectable';
 
@@ -14,11 +15,25 @@ export interface Summary<T> {
   type?: CompileTypeSummary;
 }
 
+export abstract class SummaryResolver<T> {
+  abstract isLibraryFile(fileName: string): boolean;
+  abstract getLibraryFileName(fileName: string): string|null;
+  abstract resolveSummary(reference: T): Summary<T>|null;
+  abstract getSymbolsOf(filePath: string): T[];
+  abstract getImportAs(reference: T): T;
+  abstract addSummary(summary: Summary<T>): void;
+}
+
 @CompilerInjectable()
-export class SummaryResolver<T> {
+export class JitSummaryResolver implements SummaryResolver<Type<any>> {
+  private _summaries = new Map<Type<any>, Summary<Type<any>>>();
+
   isLibraryFile(fileName: string): boolean { return false; };
   getLibraryFileName(fileName: string): string|null { return null; }
-  resolveSummary(reference: T): Summary<T>|null { return null; };
-  getSymbolsOf(filePath: string): T[] { return []; }
-  getImportAs(reference: T): T { return reference; }
+  resolveSummary(reference: Type<any>): Summary<Type<any>>|null {
+    return this._summaries.get(reference) || null;
+  };
+  getSymbolsOf(filePath: string): Type<any>[] { return []; }
+  getImportAs(reference: Type<any>): Type<any> { return reference; }
+  addSummary(summary: Summary<Type<any>>) { this._summaries.set(summary.symbol, summary); };
 }