| // Copyright 2018 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_MESSAGE_CENTER_MESSAGE_CENTER_SCROLL_BAR_H_ |
| #define ASH_SYSTEM_MESSAGE_CENTER_MESSAGE_CENTER_SCROLL_BAR_H_ |
| |
| #include "ui/events/event.h" |
| #include "ui/views/controls/scrollbar/overlay_scroll_bar.h" |
| |
| namespace ash { |
| |
| // The scroll bar for message center. This is basically views::OverlayScrollBar |
| // but also records the metrics for the type of scrolling. Only the first event |
| // after the message center opens is recorded. |
| class MessageCenterScrollBar : public views::OverlayScrollBar { |
| public: |
| class Observer { |
| public: |
| // Called when scroll event is triggered. |
| virtual void OnMessageCenterScrolled() = 0; |
| virtual ~Observer() = default; |
| }; |
| |
| // |observer| can be null. |
| explicit MessageCenterScrollBar(Observer* observer); |
| |
| private: |
| // View overrides: |
| bool OnKeyPressed(const ui::KeyEvent& event) override; |
| bool OnMouseWheel(const ui::MouseWheelEvent& event) override; |
| |
| // ui::EventHandler overrides: |
| void OnGestureEvent(ui::GestureEvent* event) override; |
| |
| // views::ScrollDelegate overrides: |
| bool OnScroll(float dx, float dy) override; |
| |
| // False if no event is recorded yet. True if the first event is recorded. |
| bool stats_recorded_ = false; |
| |
| Observer* const observer_; |
| |
| DISALLOW_COPY_AND_ASSIGN(MessageCenterScrollBar); |
| }; |
| |
| } // namespace ash |
| |
| #endif // ASH_SYSTEM_MESSAGE_CENTER_MESSAGE_CENTER_SCROLL_BAR_H_ |