chromeos: Move files in //ash/common to //ash, part 2

ash/display/shutdown_observer_chromeos.cc

 // Copyright 2016 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/display/shutdown_observer_chromeos.h"
 
-#include "ash/common/wm_shell.h"
+#include "ash/wm_shell.h"
 #include "ui/display/manager/chromeos/display_configurator.h"
 
 namespace ash {
 
 ShutdownObserver::ShutdownObserver(
     display::DisplayConfigurator* display_configurator)
     : display_configurator_(display_configurator) {
   WmShell::Get()->AddShellObserver(this);
 }
 
 ShutdownObserver::~ShutdownObserver() {
   WmShell::Get()->RemoveShellObserver(this);
 }
 
 void ShutdownObserver::OnAppTerminating() {
   // Stop handling display configuration events once the shutdown
   // process starts. crbug.com/177014.
   display_configurator_->PrepareForExit();
 }
 
 }  // namespace ash