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

ash/system/bluetooth/bluetooth_observer.h

 // 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.
 
-#ifndef ASH_COMMON_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_OBSERVER_H_
-#define ASH_COMMON_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_OBSERVER_H_
+#ifndef ASH_SYSTEM_BLUETOOTH_BLUETOOTH_OBSERVER_H_
+#define ASH_SYSTEM_BLUETOOTH_BLUETOOTH_OBSERVER_H_
 
 namespace ash {
 
 class BluetoothObserver {
  public:
   virtual ~BluetoothObserver() {}
 
   virtual void OnBluetoothRefresh() = 0;
   virtual void OnBluetoothDiscoveringChanged() = 0;
 };
 
 }  // namespace ash
 
-#endif  // ASH_COMMON_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_OBSERVER_H_
+#endif  // ASH_SYSTEM_BLUETOOTH_BLUETOOTH_OBSERVER_H_