chromeos: Move files in //ash/common to //ash, part 1

ash/common/system/chromeos/session/last_window_closed_observer.h

Index: ash/common/system/chromeos/session/last_window_closed_observer.h
diff --git a/ash/common/system/chromeos/session/last_window_closed_observer.h b/ash/common/system/chromeos/session/last_window_closed_observer.h
deleted file mode 100644
index c19df95a495142567e0b18f66294e1d9744ed7fb..0000000000000000000000000000000000000000
--- a/ash/common/system/chromeos/session/last_window_closed_observer.h
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright 2014 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_COMMON_SYSTEM_CHROMEOS_SESSION_LAST_WINDOW_CLOSED_OBSERVER_H_
-#define ASH_COMMON_SYSTEM_CHROMEOS_SESSION_LAST_WINDOW_CLOSED_OBSERVER_H_
-
-#include "ash/ash_export.h"
-
-namespace ash {
-
-class ASH_EXPORT LastWindowClosedObserver {
- public:
-  virtual void OnLastWindowClosed() = 0;
-
- protected:
-  virtual ~LastWindowClosedObserver() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_COMMON_SYSTEM_CHROMEOS_SESSION_LAST_WINDOW_CLOSED_OBSERVER_H_