feat(injector): support forwardRef in toAlias

modules/angular2/src/di/binding.ts

@@ -236,8 +236,7 @@ export class Binding {
       resolvedDeps = _EMPTY_LIST;
     }
 
-    return new ResolvedBinding(Key.get(resolveForwardRef(this.token)), factoryFn, resolvedDeps,
-                               isAsync);
+    return new ResolvedBinding(Key.get(this.token), factoryFn, resolvedDeps, isAsync);
   }
 }
 
@@ -492,5 +491,5 @@ function _extractToken(typeOrFunc, annotations) {
 }
 
 function _createDependency(token, asPromise, lazy, optional, depProps): Dependency {
-  return new Dependency(Key.get(resolveForwardRef(token)), asPromise, lazy, optional, depProps);
+  return new Dependency(Key.get(token), asPromise, lazy, optional, depProps);
 }

modules/angular2/src/di/forward_ref.dart

@@ -1,6 +1,6 @@
 library angular2.di.forward_ref;
 
-typedef Type ForwardRefFn();
+typedef dynamic ForwardRefFn();
 
 /**
  * Dart does not have the forward ref problem, so this function is a noop.

modules/angular2/src/di/key.ts

@@ -1,6 +1,7 @@
 import {MapWrapper} from 'angular2/src/facade/collection';
 import {stringify, CONST, Type, isBlank, BaseException} from 'angular2/src/facade/lang';
 import {TypeLiteral} from './type_literal';
+import {resolveForwardRef} from './forward_ref';
 
 export {TypeLiteral} from './type_literal';
 
@@ -38,7 +39,7 @@ export class Key {
   /**
    * Retrieves a `Key` for a token.
    */
-  static get(token): Key { return _globalKeyRegistry.get(token); }
+  static get(token): Key { return _globalKeyRegistry.get(resolveForwardRef(token)); }
 
   /**
    * @returns the number of keys registered in the system.