Remove linked_ptr from ash

ash/first_run/desktop_cleaner.h

 // Copyright 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.
 
 #ifndef ASH_FIRST_RUN_DESKTOP_CLEANER_
 #define ASH_FIRST_RUN_DESKTOP_CLEANER_
 
 #include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
-#include "base/memory/linked_ptr.h"
 
 namespace ash {
 class ContainerHider;
 class NotificationBlocker;
 
 namespace test {
 class FirstRunHelperTest;
 }
 
 // Class used to "clean" ash desktop, i.e. hide all windows and notifications.
 class ASH_EXPORT DesktopCleaner {
  public:
   DesktopCleaner();
   ~DesktopCleaner();
 
  private:
   // Returns the list of containers that DesctopCleaner hides.
   static std::vector<int> GetContainersToHideForTest();
 
-  std::vector<linked_ptr<ContainerHider>> container_hiders_;
+  std::vector<std::unique_ptr<ContainerHider>> container_hiders_;
   std::unique_ptr<NotificationBlocker> notification_blocker_;
 
   friend class ash::test::FirstRunHelperTest;
   DISALLOW_COPY_AND_ASSIGN(DesktopCleaner);
 };
 
 }  // namespace ash
 
 #endif  // ASH_FIRST_RUN_DESKTOP_CLEANER_