feat(forms): update FormBuilder to support async validations

Closes #5020

modules/angular2/test/core/forms/form_builder_spec.ts

@@ -9,9 +9,13 @@ import {
   afterEach,
   el
 } from 'angular2/testing_internal';
-import {Control, FormBuilder, Validators} from 'angular2/core';
+import {Control, FormBuilder} from 'angular2/core';
+import {PromiseWrapper} from 'angular2/src/core/facade/promise';
 
 export function main() {
+  function syncValidator(_) { return null; }
+  function asyncValidator(_) { return PromiseWrapper.resolve(null); }
+
   describe("Form Builder", () => {
     var b;
 
@@ -24,18 +28,21 @@ export function main() {
     });
 
     it("should create controls from an array", () => {
-      var g = b.group({"login": ["some value"], "password": ["some value", Validators.required]});
+      var g = b.group(
+          {"login": ["some value"], "password": ["some value", syncValidator, asyncValidator]});
 
       expect(g.controls["login"].value).toEqual("some value");
       expect(g.controls["password"].value).toEqual("some value");
-      expect(g.controls["password"].validator).toEqual(Validators.required);
+      expect(g.controls["password"].validator).toEqual(syncValidator);
+      expect(g.controls["password"].asyncValidator).toEqual(asyncValidator);
     });
 
     it("should use controls", () => {
-      var g = b.group({"login": b.control("some value", Validators.required)});
+      var g = b.group({"login": b.control("some value", syncValidator, asyncValidator)});
 
       expect(g.controls["login"].value).toEqual("some value");
-      expect(g.controls["login"].validator).toBe(Validators.required);
+      expect(g.controls["login"].validator).toBe(syncValidator);
+      expect(g.controls["login"].asyncValidator).toBe(asyncValidator);
     });
 
     it("should create groups with optional controls", () => {
@@ -45,16 +52,21 @@ export function main() {
     });
 
     it("should create groups with a custom validator", () => {
-      var g = b.group({"login": "some value"}, {"validator": Validators.nullValidator});
+      var g = b.group({"login": "some value"},
+                      {"validator": syncValidator, "asyncValidator": asyncValidator});
 
-      expect(g.validator).toBe(Validators.nullValidator);
+      expect(g.validator).toBe(syncValidator);
+      expect(g.asyncValidator).toBe(asyncValidator);
     });
 
     it("should create control arrays", () => {
       var c = b.control("three");
-      var a = b.array(["one", ["two", Validators.required], c, b.array(['four'])]);
+      var a = b.array(["one", ["two", syncValidator], c, b.array(['four'])], syncValidator,
+                      asyncValidator);
 
       expect(a.value).toEqual(['one', 'two', 'three', ['four']]);
+      expect(a.validator).toBe(syncValidator);
+      expect(a.asyncValidator).toBe(asyncValidator);
     });
   });
 }