chromeos: Move files in //ash/common to //ash, part 2

ash/common/shelf/ink_drop_button_listener.h

-// 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_COMMON_SHELF_INK_DROP_BUTTON_LISTENER_H_
-#define ASH_COMMON_SHELF_INK_DROP_BUTTON_LISTENER_H_
-
-#include "ash/ash_export.h"
-
-namespace ui {
-class Event;
-}
-
-namespace views {
-class Button;
-class InkDrop;
-}
-
-namespace ash {
-
-// An interface used by buttons on shelf to notify ShelfView when they are
-// pressed. |ink_drop| is used to do appropriate ink drop animation based on the
-// action performed.
-// TODO(mohsen): A better approach would be to return a value indicating the
-// type of action performed such that the button can animate the ink drop.
-// Currently, it is not possible because showing menu is synchronous and blocks
-// the call. Fix this after menu is converted to synchronous.  Long-term, the
-// return value can be merged into ButtonListener.
-class ASH_EXPORT InkDropButtonListener {
- public:
-  virtual void ButtonPressed(views::Button* sender,
-                             const ui::Event& event,
-                             views::InkDrop* ink_drop) = 0;
-
- protected:
-  virtual ~InkDropButtonListener() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_COMMON_SHELF_INK_DROP_BUTTON_LISTENER_H_