New kiosk UI: handle edge cases

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

Index: chrome/browser/resources/chromeos/login/screen_gaia_signin.js
diff --git a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
index ad4c84125c9317cda61d842ba59ec09e021d8e79..86565520b3d6fc1860459afbc036c5f31377c62f 100644
--- a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
+++ b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
@@ -28,7 +28,8 @@ login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
       'updateAuthExtension',
       'setAuthenticatedUserEmail',
       'doReload',
-      'onFrameError'
+      'onFrameError',
+      'updateCancelButtonState'
     ],
 
     /**
@@ -73,6 +74,13 @@ login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
     cancelAllowed_: undefined,
 
     /**
+     * Whether we should show user pods on the login screen.
+     * @type {boolean}
+     * @private
+     */
+    isShowUsers_: undefined,
+
+    /**
      * SAML password confirmation attempt count.
      * @type {number}
      */
@@ -297,9 +305,8 @@ login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
       $('createManagedUserNoManagerText').textContent =
           data.managedUsersRestrictionReason;
 
-      // Allow cancellation of screen only when user pods can be displayed.
-      this.cancelAllowed_ = data.isShowUsers && $('pod-row').pods.length;
-      $('login-header-bar').allowCancel = this.cancelAllowed_;
+      this.isShowUsers_ = data.isShowUsers;
+      this.updateCancelButtonState();
 
       // Sign-in right panel is hidden if all of its items are hidden.
       var noRightPanel = $('gaia-signin-reason').hidden &&
@@ -322,6 +329,15 @@ login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
     },
 
     /**
+     * Updates [Cancel] button state. Allow cancellation of screen only when
+     * user pods can be displayed.
+     */
+    updateCancelButtonState: function() {
+      this.cancelAllowed_ = this.isShowUsers_ && $('pod-row').pods.length;
+      $('login-header-bar').allowCancel = this.cancelAllowed_;
+    },
+
+    /**
      * Whether the current auth flow is SAML.
      */
     isSAML: function() {