ash: Add basic prediction code to the laser pointer.

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/macros.h"
+#include "base/time/time.h"
 #include "ui/aura/window_observer.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/geometry/point_f.h"
 
 namespace base {
 class Timer;
 }
 
 namespace ash {
 
@@ skipping 37 matching lines @@
   // Destroys |laser_pointer_view_|, if it exists.
   void DestroyLaserPointerView();
 
   void RestartTimer();
 
   // Timer which will add a new stationary point when the stylus stops moving.
   // This will remove points that are too old.
   std::unique_ptr<base::Timer> stationary_timer_;
   int stationary_timer_repeat_count_ = 0;
 
+  // The presentation delay used for prediction by the laser pointer view.
+  base::TimeDelta presentation_delay_;
+
   bool enabled_ = false;
 
   // |is_fading_away_| determines whether the laser pointer view should accept
   // points normally, or just advance the |laser_points_| time so that current
   // points start fading away. This should be set to true when the view is about
   // to be destroyed, such as when the stylus is released.
   bool is_fading_away_ = false;
 
   // The last seen stylus location in screen coordinates.
   gfx::PointF current_stylus_location_;
 
   // |laser_pointer_view_| will only hold an instance when the laser pointer is
   // enabled and activated (pressed or dragged).
   std::unique_ptr<LaserPointerView> laser_pointer_view_;
 
   DISALLOW_COPY_AND_ASSIGN(LaserPointerController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_LASER_LASER_POINTER_CONTROLLER_H_