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

ash/system/bluetooth/bluetooth_observer.h

Index: ash/system/bluetooth/bluetooth_observer.h
diff --git a/ash/system/bluetooth/bluetooth_observer.h b/ash/system/bluetooth/bluetooth_observer.h
deleted file mode 100644
index 1c1bf4fa4d0158f2ff4865ebe84ee93eb6484d89..0000000000000000000000000000000000000000
--- a/ash/system/bluetooth/bluetooth_observer.h
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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_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_SYSTEM_BLUETOOTH_BLUETOOTH_OBSERVER_H_