ChromeOS: user whitelist check should happen before entering password.

chrome/browser/resources/gaia_auth_host/authenticator.js

Index: chrome/browser/resources/gaia_auth_host/authenticator.js
diff --git a/chrome/browser/resources/gaia_auth_host/authenticator.js b/chrome/browser/resources/gaia_auth_host/authenticator.js
index 870b368258f4f6e5aa5bad23b0bbf15c8259df68..bbdd98278cd90bbcd16d0e76d71bf201843eabed 100644
--- a/chrome/browser/resources/gaia_auth_host/authenticator.js
+++ b/chrome/browser/resources/gaia_auth_host/authenticator.js
@@ -445,6 +445,10 @@ cr.define('cr.login', function() {
       this.dispatchEvent(new CustomEvent('backButton', {detail: msg.show}));
     } else if (msg.method == 'showView') {
       this.dispatchEvent(new Event('showView'));
+    } else if (msg.method == 'identifierEntered') {
+      this.dispatchEvent(new CustomEvent(
+          'identifierEntered',
+          {detail: {accountIdentifier: msg.accountIdentifier}}));
     } else {
       console.warn('Unrecognized message from GAIA: ' + msg.method);
     }