Revert "chromeos: Move files in //ash/common to //ash, part 3"

ash/wm_display_observer.h

Index: ash/wm_display_observer.h
diff --git a/ash/wm_display_observer.h b/ash/wm_display_observer.h
deleted file mode 100644
index a9c1f0c551d10f198153998526468bc89ba4287b..0000000000000000000000000000000000000000
--- a/ash/wm_display_observer.h
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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.
-
-#ifndef ASH_WM_DISPLAY_OBSERVER_H_
-#define ASH_WM_DISPLAY_OBSERVER_H_
-
-#include "ash/ash_export.h"
-
-namespace ash {
-
-// Used to track changes in display configuration.
-class ASH_EXPORT WmDisplayObserver {
- public:
-  // Called prior to the display configuration changing.
-  virtual void OnDisplayConfigurationChanging() {}
-
-  // Called after the display configure changed.
-  virtual void OnDisplayConfigurationChanged() {}
-
- protected:
-  virtual ~WmDisplayObserver() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_DISPLAY_OBSERVER_H_