feat(forms): introduce AsyncValidator interface (#13483)

Closes #13398

modules/@angular/forms/test/reactive_integration_spec.ts

@@ -8,7 +8,7 @@
 
 import {Component, Directive, EventEmitter, Input, Output, Type, forwardRef} from '@angular/core';
 import {ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
-import {AbstractControl, ControlValueAccessor, FormArray, FormControl, FormGroup, FormGroupDirective, FormsModule, NG_ASYNC_VALIDATORS, NG_VALIDATORS, NG_VALUE_ACCESSOR, NgControl, ReactiveFormsModule, Validator, Validators} from '@angular/forms';
+import {AbstractControl, AsyncValidator, ControlValueAccessor, FormArray, FormControl, FormGroup, FormGroupDirective, FormsModule, NG_ASYNC_VALIDATORS, NG_VALIDATORS, NG_VALUE_ACCESSOR, NgControl, ReactiveFormsModule, Validators} from '@angular/forms';
 import {By} from '@angular/platform-browser/src/dom/debug/by';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {dispatchEvent} from '@angular/platform-browser/testing/browser_util';
@@ -1951,7 +1951,7 @@ class LoginIsEmptyValidator {
     multi: true
   }]
 })
-class UniqLoginValidator implements Validator {
+class UniqLoginValidator implements AsyncValidator {
   @Input('uniq-login-validator') expected: any;
 
   validate(c: AbstractControl) { return uniqLoginAsyncValidator(this.expected)(c); }

modules/@angular/forms/test/template_integration_spec.ts

@@ -8,7 +8,7 @@
 
 import {Component, Directive, Input, Type, forwardRef} from '@angular/core';
 import {ComponentFixture, TestBed, async, fakeAsync, tick} from '@angular/core/testing';
-import {AbstractControl, ControlValueAccessor, FormsModule, NG_ASYNC_VALIDATORS, NG_VALUE_ACCESSOR, NgForm, Validator} from '@angular/forms';
+import {AbstractControl, AsyncValidator, ControlValueAccessor, FormsModule, NG_ASYNC_VALIDATORS, NG_VALUE_ACCESSOR, NgForm} from '@angular/forms';
 import {By} from '@angular/platform-browser/src/dom/debug/by';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {dispatchEvent} from '@angular/platform-browser/testing/browser_util';
@@ -1493,7 +1493,7 @@ class NgModelEmailValidator {
     {provide: NG_ASYNC_VALIDATORS, useExisting: forwardRef(() => NgAsyncValidator), multi: true}
   ]
 })
-class NgAsyncValidator implements Validator {
+class NgAsyncValidator implements AsyncValidator {
   validate(c: AbstractControl) { return Promise.resolve(null); }
 }
 

modules/@angular/forms/test/validators_spec.ts

@@ -12,6 +12,7 @@ import {AbstractControl, FormArray, FormControl, FormGroup, Validators} from '@a
 import {Observable} from 'rxjs/Observable';
 
 import {normalizeAsyncValidator} from '../src/directives/normalize_validator';
+import {AsyncValidator} from '../src/directives/validators';
 import {EventEmitter} from '../src/facade/async';
 
 export function main() {
@@ -23,10 +24,11 @@ export function main() {
     };
   }
 
-  class AsyncValidatorDirective {
+  class AsyncValidatorDirective implements AsyncValidator {
     constructor(private expected: string, private error: any) {}
 
-    validate(c: any): {[key: string]: any;} {
+    validate(c: any): Observable < { [key: string]: any; }
+    > {
       return Observable.create((obs: any) => {
         const error = this.expected !== c.value ? this.error : null;
         obs.next(error);