mash: Migrate tray IME view to wm common types, move to //ash/common

ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_observer.h

 // 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_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_
-#define ASH_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_
+#ifndef ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_
+#define ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_
 
 #include "ash/ash_export.h"
 
+namespace ash {
+
 class ASH_EXPORT VirtualKeyboardObserver {
  public:
   virtual ~VirtualKeyboardObserver() {}
 
   // Notifies when the keyboard is suppressed.
   virtual void OnKeyboardSuppressionChanged(bool suppressed) = 0;
 };
 
-#endif  // ASH_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_
+}  // namespace ash
+
+#endif  // ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_OBSERVER_H_