Focus kept on login screen.

chrome/browser/ui/ash/session_state_delegate_chromeos.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/ash/session_state_delegate_chromeos.h"
 
 #include "ash/session_state_observer.h"
 #include "base/logging.h"
 #include "chrome/browser/chromeos/login/screen_locker.h"
 #include "chrome/browser/chromeos/login/user.h"
+#include "chrome/browser/chromeos/login/user_adding_screen.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
 
 SessionStateDelegateChromeos::SessionStateDelegateChromeos() {
   chromeos::UserManager::Get()->AddSessionStateObserver(this);
 }
 
 SessionStateDelegateChromeos::~SessionStateDelegateChromeos() {
 }
@@ skipping 26 matching lines @@
   VLOG(1) << "Requesting screen lock from SessionStateDelegate";
   chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
       RequestLockScreen();
 }
 
 void SessionStateDelegateChromeos::UnlockScreen() {
   // This is used only for testing thus far.
   NOTIMPLEMENTED();
 }
 
+bool SessionStateDelegateChromeos::IsUserSessionBlocked() const {
+  return !IsActiveUserSessionStarted() || IsScreenLocked() ||
+         chromeos::UserAddingScreen::Get()->IsRunning();

[sky, 2013/07/15 22:23:36]

Is that last statement really needed?

[dzhioev (left Google), 2013/07/16 09:54:36]

Yes, it is new UI similar to login/oobe/lock needed to add users into
multi-profile session.

+}
+
 const base::string16 SessionStateDelegateChromeos::GetUserDisplayName(
     ash::MultiProfileIndex index) const {
   DCHECK_LT(index, NumberOfLoggedInUsers());
   return chromeos::UserManager::Get()->
              GetLRULoggedInUsers()[index]->display_name();
 }
 
 const std::string SessionStateDelegateChromeos::GetUserEmail(
     ash::MultiProfileIndex index) const {
   DCHECK_LT(index, NumberOfLoggedInUsers());
@@ skipping 31 matching lines @@
     ash::SessionStateObserver* observer) {
   session_state_observer_list_.RemoveObserver(observer);
 }
 
 void SessionStateDelegateChromeos::ActiveUserChanged(
     const chromeos::User* active_user) {
   FOR_EACH_OBSERVER(ash::SessionStateObserver,
                     session_state_observer_list_,
                     ActiveUserChanged(active_user->email()));
 }