Add Active Directory login UI tests

chrome/browser/resources/chromeos/login/screen_gaia_signin.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview Oobe signin screen implementation.
  */
 
 login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
   // GAIA animation guard timer. Started when GAIA page is loaded
@@ skipping 1102 matching lines @@
       this.loading = !show;
 
       if (show)
         $('gaia-whitelist-error').submitButton.focus();
       else
         Oobe.showSigninUI();
 
       this.updateControlsState();
     },
 
-    invalidateAd: function(username) {
+    invalidateAd: function(username, errorState) {

[achuithb, 2017/03/07 15:07:04]

Where is this used in the test?

[Roman Sorokin (ftl), 2017/03/07 16:32:05]

GaiaScreenHandler passes it depending on answer from FakeAuthPolicyClient

       if (this.screenMode_ != ScreenMode.AD_AUTH)
         return;
       var adAuthUI = this.getSigninFrame_();
       adAuthUI.setUser(username);
-      adAuthUI.setInvalid(ACTIVE_DIRECTORY_ERROR_STATE.BAD_PASSWORD);
+      adAuthUI.setInvalid(errorState);
       this.loading = false;
+      Oobe.getInstance().headerHidden = false;
     }
   };
 });