Fix the flaky test KioskTest.LaunchAppUserCancel

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

 // Copyright (c) 2013 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.
 
 #include "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 901 matching lines @@
 
 void SigninScreenHandler::OnPreferencesChanged() {
   // Make sure that one of the login UI is fully functional now, otherwise
   // preferences update would be picked up next time it will be shown.
   if (!webui_visible_) {
     LOG(WARNING) << "Login UI is not active - postponed prefs change.";
     preferences_changed_delayed_ = true;
     return;
   }
 
+  preferences_changed_delayed_ = false;
+
+  if (!delegate_)
+    return;
+
   // Send the updated user list to the UI.
-  if (delegate_)
-    delegate_->HandleGetUsers();
+  delegate_->HandleGetUsers();
+  if (GetCurrentScreen() == OobeScreen::SCREEN_ACCOUNT_PICKER &&
+      delegate_->ShowUsersHasChanged() &&
+      !delegate_->IsShowUsers()) {
+    // We are at the account picker screen and the POD setting has changed
+    // to be disabled. We need to show the add user page.
+    HandleShowAddUser(nullptr);
+    return;
+  }
 
-  if (delegate_ && !delegate_->IsShowUsers()) {
-    HandleShowAddUser(nullptr);
-  } else {
+  if (delegate_->AllowNewUserChanged() || ui_state_ == UI_STATE_UNKNOWN) {
+    // We need to reload GAIA if UI_STATE_UNKNOWN or the allow new user setting
+    // has changed so that reloaded GAIA shows/hides the option to create a new
+    // account.
     UpdateUIState(UI_STATE_ACCOUNT_PICKER, nullptr);
   }
-
-  preferences_changed_delayed_ = false;
 }
 
 void SigninScreenHandler::ResetSigninScreenHandlerDelegate() {
   SetDelegate(nullptr);
 }
 
 void SigninScreenHandler::ShowError(int login_attempts,
                                     const std::string& error_text,
                                     const std::string& help_link_text,
                                     HelpAppLauncher::HelpTopic help_topic_id) {
@@ skipping 525 matching lines @@
 }
 
 void SigninScreenHandler::OnFeedbackFinished() {
   CallJS("login.UnrecoverableCryptohomeErrorScreen.resumeAfterFeedbackUI");
 
   // Recreate user's cryptohome after the feedback is attempted.
   HandleResyncUserData();
 }
 
 }  // namespace chromeos