Remove unused linked_ptr inclusion

ui/wm/core/shadow_controller.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 "ui/wm/core/shadow_controller.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
-#include "base/memory/linked_ptr.h"
 #include "base/scoped_observer.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/env_observer.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/aura/window_property.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/layer.h"
 #include "ui/wm/core/shadow.h"
@@ skipping 254 matching lines @@
   activation_client_->RemoveObserver(this);
 }
 
 void ShadowController::OnWindowActivated(ActivationReason reason,
                                          aura::Window* gained_active,
                                          aura::Window* lost_active) {
   impl_->OnWindowActivated(reason, gained_active, lost_active);
 }
 
 }  // namespace wm