Reland - cros: Add CHECK for screen unlock problem

chrome/browser/chromeos/login/screen_locker.cc

 // Copyright (c) 2012 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/chromeos/login/screen_locker.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/desktop_background/desktop_background_controller.h"
@@ skipping 305 matching lines @@
 void ScreenLocker::InitClass() {
   g_screen_lock_observer.Get();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // ScreenLocker, private:
 
 ScreenLocker::~ScreenLocker() {
   DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
   ClearErrors();
-  ash::Shell::GetInstance()->
+  bool moved = ash::Shell::GetInstance()->
       desktop_background_controller()->MoveDesktopToUnlockedContainer();
+  // If we didn't reparent the desktop background then the screen would be
+  // unlocked but the user's windows are hidden, making the UI unusable.
+  // Similar symptoms are happening in the field. Check if this is the cause.
+  // See crbug.com/149043
+  CHECK(moved);
+  LOG(WARNING) << "JAMESDEBUG screen locked moved " << moved;
 
   screen_locker_ = NULL;
   bool state = false;
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_SCREEN_LOCK_STATE_CHANGED,
       content::Source<ScreenLocker>(this),
       content::Details<bool>(&state));
   DBusThreadManager::Get()->GetSessionManagerClient()->
       NotifyLockScreenDismissed();
 }
@@ skipping 14 matching lines @@
 
   bool state = true;
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_SCREEN_LOCK_STATE_CHANGED,
       content::Source<ScreenLocker>(this),
       content::Details<bool>(&state));
   DBusThreadManager::Get()->GetSessionManagerClient()->NotifyLockScreenShown();
 }
 
 }  // namespace chromeos