Modal window in user session not blocks user adding screen.

ash/session_state_delegate_stub.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 "ash/session_state_delegate_stub.h"
 
 #include "ash/shell.h"
 #include "ash/shell/example_factory.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 30 matching lines @@
   shell::CreateLockScreen();
   screen_locked_ = true;
   Shell::GetInstance()->UpdateShelfVisibility();
 }
 
 void SessionStateDelegateStub::UnlockScreen() {
   screen_locked_ = false;
   Shell::GetInstance()->UpdateShelfVisibility();
 }
 
+bool SessionStateDelegateStub::IsUserSessionBlocked() const  {
+  return !IsActiveUserSessionStarted() || IsScreenLocked();
+}
+
 const base::string16 SessionStateDelegateStub::GetUserDisplayName(
     MultiProfileIndex index) const {
   return UTF8ToUTF16("stub-user");
 }
 
 const std::string SessionStateDelegateStub::GetUserEmail(
     MultiProfileIndex index) const {
   return "stub-user@domain.com";
 }
 
@@ skipping 10 matching lines @@
 
 void SessionStateDelegateStub::AddSessionStateObserver(
     ash::SessionStateObserver* observer) {
 }
 
 void SessionStateDelegateStub::RemoveSessionStateObserver(
     ash::SessionStateObserver* observer) {
 }
 
 }  // namespace ash