refactor(upgrade/upgrade_adapter): use `Deferred` helper

Making Angular 1's `$compile` asynchronous by chaining injector promises
in linking functions can cause flickering views in applications.

modules/@angular/upgrade/src/upgrade_adapter.ts

@@ -14,7 +14,7 @@ import {NG1_COMPILE, NG1_INJECTOR, NG1_PARSE, NG1_ROOT_SCOPE, NG1_TESTABILITY, N
 import {DowngradeNg2ComponentAdapter} from './downgrade_ng2_adapter';
 import {ComponentInfo, getComponentInfo} from './metadata';
 import {UpgradeNg1ComponentAdapterBuilder} from './upgrade_ng1_adapter';
-import {controllerKey, onError} from './util';
+import {controllerKey, onError, Deferred} from './util';
 
 let upgradeCount: number = 0;
 
@@ -326,7 +326,7 @@ export class UpgradeAdapter {
     const componentFactoryRefMap: ComponentFactoryRefMap = {};
     const ng1Module = angular.module(this.idPrefix, modules);
     let ng1BootstrapPromise: Promise<any>;
-    let ng1compilePromise: Promise<any>;
+    const ng2BootstrapDeferred = new Deferred();
     ng1Module.factory(NG2_INJECTOR, () => moduleRef.injector.get(Injector))
         .value(NG2_ZONE, ngZone)
         .factory(NG2_COMPILER, () => moduleRef.injector.get(Compiler))
@@ -375,7 +375,6 @@ export class UpgradeAdapter {
           }
         ]);
 
-    ng1compilePromise = new Promise((resolve, reject) => {
     ng1Module.run([
       '$injector', '$rootScope',
       (injector: angular.IInjectorService, rootScope: angular.IRootScopeService) => {
@@ -417,12 +416,11 @@ export class UpgradeAdapter {
                       next: (_: any) => ngZone.runOutsideAngular(() => rootScope.$evalAsync())
                     });
                   })
-                    .then(resolve, reject);
+                  .then(ng2BootstrapDeferred.resolve, ng2BootstrapDeferred.reject);
             })
-              .catch(reject);
+            .catch(ng2BootstrapDeferred.reject);
         }
       ]);
-    });
 
     // Make sure resumeBootstrap() only exists if the current bootstrap is deferred
     const windowAngular = (window as any /** TODO #???? */)['angular'];
@@ -443,7 +441,7 @@ export class UpgradeAdapter {
       }
     });
 
-    Promise.all([ng1BootstrapPromise, ng1compilePromise]).then(() => {
+    Promise.all([ng1BootstrapPromise, ng2BootstrapDeferred.promise]).then(() => {
       moduleRef.injector.get(NgZone).run(() => {
         if (rootScopePrototype) {
           rootScopePrototype.$apply = original$applyFn;  // restore original $apply

modules/@angular/upgrade/src/util.ts

@@ -22,3 +22,16 @@ export function onError(e: any) {
 export function controllerKey(name: string): string {
   return '$' + name + 'Controller';
 }
+
+export class Deferred<R> {
+  promise: Promise<R>;
+  resolve: (value?: R|PromiseLike<R>) => void;
+  reject: (error?: any) => void;
+
+  constructor() {
+    this.promise = new Promise((res, rej) => {
+      this.resolve = res;
+      this.reject = rej;
+    });
+  }
+}