Laser tool blocks events from propagating.

ash/laser/laser_pointer_controller.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_LASER_LASER_POINTER_CONTROLLER_H_
+#define ASH_LASER_LASER_POINTER_CONTROLLER_H_
+
+#include <memory>
+
+#include "ash/ash_export.h"
+#include "base/timer/timer.h"

[James Cook, 2016/09/14 17:52:27]

You can forward declare this

[sammiequon, 2016/09/14 21:44:09]

Done.

+#include "ui/aura/window_observer.h"
+#include "ui/events/event.h"
+#include "ui/events/event_handler.h"
+#include "ui/gfx/geometry/point.h"
+
+namespace base {
+class Timer;
+}
+
+namespace ui {
+class LocatedEvent;
+class MouseEvent;
+class TouchEvent;
+}
+
+namespace ash {
+
+class LaserPointerView;
+
+// Controller for the laser pointer functionality. Enables/disables laser
+// pointer as well as receives points and passes them off to be rendered.
+class ASH_EXPORT LaserPointerController : public ui::EventHandler,
+                                          public aura::WindowObserver {
+ public:
+  explicit LaserPointerController();

[James Cook, 2016/09/14 17:52:27]

no explicit

[sammiequon, 2016/09/14 21:44:09]

Done.

+  ~LaserPointerController() override;
+
+  // Turns the laser pointer feature on or off. The user still has to press and
+  // drag to see the laser pointer.
+  void SetEnabled(bool enabled);
+
+ private:
+  friend class LaserPointerControllerTestApi;
+
+  // ui::EventHandler:
+  void OnMouseEvent(ui::MouseEvent* event) override;
+
+  // aura::WindowObserver:
+  void OnWindowDestroying(aura::Window* window) override;
+
+  void StopTimer();
+  void SwitchTargetRootWindowIfNeeded();

[James Cook, 2016/09/14 17:52:26]

nit: document (why does it need to switch? if needed means when?)

[sammiequon, 2016/09/14 21:44:09]

Done.

+
+  // Timer callback which adds a point where the mouse was last seen. This
+  // allows the trail to fade away when the mouse is stationary.

[James Cook, 2016/09/14 17:52:27]

nice comment

[sammiequon, 2016/09/14 21:44:09]

thanks

+  void AddStationaryPoint();
+
+  // Timer which will add a new stationary point when the mouse stops moving.
+  // This will remove points that are too old.
+  std::unique_ptr<base::Timer> timer_;

[James Cook, 2016/09/14 17:52:27]

optional: How about stationary_timer_ or mouse_move_timer_?

[sammiequon, 2016/09/14 21:44:09]

Done.

+  int timer_repeat_count_ = 0;
+
+  bool enabled_ = false;
+
+  gfx::Point current_mouse_location_;

[James Cook, 2016/09/14 17:52:27]

Document screen coords or root coords. Or rename to ..._in_screen.

[sammiequon, 2016/09/14 21:44:09]

Done.

+  // |laser_pointer_view_| will only hold an instance when the laser pointer is
+  // enabled and activated(pressed or dragged).

[James Cook, 2016/09/14 17:52:27]

nit: space after activated

[sammiequon, 2016/09/14 21:44:09]

Done.

+  std::unique_ptr<LaserPointerView> laser_pointer_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(LaserPointerController);

[James Cook, 2016/09/14 17:52:26]

#include base/macros.h

[sammiequon, 2016/09/14 21:44:09]

Done.

+};
+
+}  // namespace ash
+
+#endif  // ASH_LASER_LASER_POINTER_CONTROLLER_H_