Reland: mash: Convert TrayBackgroundView to wm common types

ash/system/tray/tray_event_filter.h

-// 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_TRAY_TRAY_EVENT_FILTER_H_
-#define ASH_SYSTEM_TRAY_TRAY_EVENT_FILTER_H_
-
-#include <set>
-
-#include "base/macros.h"
-#include "ui/views/pointer_watcher.h"
-
-namespace gfx {
-class Point;
-}
-
-namespace ui {
-class LocatedEvent;
-}
-
-namespace ash {
-class TrayBubbleWrapper;
-
-// Handles events for a tray bubble, e.g. to close the system tray bubble when
-// the user clicks outside it.
-class TrayEventFilter : public views::PointerWatcher {
- public:
-  TrayEventFilter();
-  ~TrayEventFilter() override;
-
-  void AddWrapper(TrayBubbleWrapper* wrapper);
-  void RemoveWrapper(TrayBubbleWrapper* wrapper);
-
-  // views::PointerWatcher:
-  void OnMousePressed(const ui::MouseEvent& event,
-                      const gfx::Point& location_in_screen,
-                      views::Widget* target) override;
-  void OnTouchPressed(const ui::TouchEvent& event,
-                      const gfx::Point& location_in_screen,
-                      views::Widget* target) override;
-
- private:
-  void ProcessPressedEvent(const gfx::Point& location_in_screen,
-                           views::Widget* target);
-
-  std::set<TrayBubbleWrapper*> wrappers_;
-
-  DISALLOW_COPY_AND_ASSIGN(TrayEventFilter);
-};
-
-}  // namespace ash
-
-#endif  // ASH_SYSTEM_TRAY_TRAY_EVENT_FILTER_H_