Enable mash shelf tooltips.

ash/shelf/shelf_button_host.h

-// Copyright 2013 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_SHELF_SHELF_BUTTON_HOST_H_
-#define ASH_SHELF_SHELF_BUTTON_HOST_H_
-
-#include "ash/ash_export.h"
-#include "base/strings/string16.h"
-
-namespace ui {
-class LocatedEvent;
-}
-
-namespace views {
-class View;
-}
-
-namespace ash {
-
-// The shelf buttons communicate back to the host by way of this interface.
-// This interface is used to enable reordering the items on the shelf.
-class ASH_EXPORT ShelfButtonHost {
- public:
-  enum Pointer {
-    NONE,
-    DRAG_AND_DROP,
-    MOUSE,
-    TOUCH,
-  };
-
-  // Invoked when a pointer device is pressed on a view.
-  virtual void PointerPressedOnButton(views::View* view,
-                                      Pointer pointer,
-                                      const ui::LocatedEvent& event) = 0;
-
-  // Invoked when a pointer device is dragged over a view.
-  virtual void PointerDraggedOnButton(views::View* view,
-                                      Pointer pointer,
-                                      const ui::LocatedEvent& event) = 0;
-
-  // Invoked either if a pointer device is released or mouse capture canceled.
-  virtual void PointerReleasedOnButton(views::View* view,
-                                       Pointer pointer,
-                                       bool canceled) = 0;
-
-  // Invoked when the mouse moves on the item.
-  virtual void MouseMovedOverButton(views::View* view) = 0;
-
-  // Invoked when the mouse enters the item.
-  virtual void MouseEnteredButton(views::View* view) = 0;
-
-  // Invoked when the mouse exits the item.
-  virtual void MouseExitedButton(views::View* view) = 0;
-
-  // Invoked to get the accessible name of the item.
-  virtual base::string16 GetAccessibleName(const views::View* view) = 0;
-
- protected:
-  virtual ~ShelfButtonHost() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_SHELF_SHELF_BUTTON_HOST_H_