ash: Use floating point precision for laser pointer.

ash/laser/laser_pointer_controller.cc

 // 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.
 
 #include "ash/laser/laser_pointer_controller.h"
 
 #include "ash/common/system/chromeos/palette/palette_utils.h"
 #include "ash/laser/laser_pointer_view.h"
 #include "ash/shell.h"
 #include "ui/display/screen.h"
@@ skipping 54 matching lines @@
   // to seamlessly drag a finger between two displays like it is with a mouse.
   gfx::Point event_location = event->root_location();
   aura::Window* current_window =
       static_cast<aura::Window*>(event->target())->GetRootWindow();
 
   // Start a new laser session if the stylus is pressed but not pressed over the
   // palette.
   if (event->type() == ui::ET_TOUCH_PRESSED &&
       !palette_utils::PaletteContainsPointInScreen(event_location)) {
     DestroyLaserPointerView();
-    UpdateLaserPointerView(current_window, event_location, event);
+    UpdateLaserPointerView(current_window, event->root_location_f(), event);
   }
 
   // Do not update laser if it is in the process of fading away.
   if (event->type() == ui::ET_TOUCH_MOVED && laser_pointer_view_ &&
       !is_fading_away_) {
-    UpdateLaserPointerView(current_window, event_location, event);
+    UpdateLaserPointerView(current_window, event->root_location_f(), event);
     RestartTimer();
   }
 
   if (event->type() == ui::ET_TOUCH_RELEASED && laser_pointer_view_ &&
       !is_fading_away_) {
     is_fading_away_ = true;
-    UpdateLaserPointerView(current_window, event_location, event);
+    UpdateLaserPointerView(current_window, event->root_location_f(), event);
     RestartTimer();
   }
 }
 
 void LaserPointerController::OnWindowDestroying(aura::Window* window) {
   SwitchTargetRootWindowIfNeeded(window);
 }
 
 void LaserPointerController::SwitchTargetRootWindowIfNeeded(
     aura::Window* root_window) {
   if (!root_window) {
     DestroyLaserPointerView();
   }
 
   if (!laser_pointer_view_ && enabled_) {
     laser_pointer_view_.reset(new LaserPointerView(
         base::TimeDelta::FromMilliseconds(kPointLifeDurationMs), root_window));
   }
 }
 
 void LaserPointerController::UpdateLaserPointerView(
     aura::Window* current_window,
-    const gfx::Point& event_location,
+    const gfx::PointF& event_location,
     ui::Event* event) {
   SwitchTargetRootWindowIfNeeded(current_window);
   current_stylus_location_ = event_location;
   laser_pointer_view_->AddNewPoint(current_stylus_location_);
   event->StopPropagation();
 }
 
 void LaserPointerController::DestroyLaserPointerView() {
   // |stationary_timer_| should also be stopped so that it does not attempt to
   // add points when |laser_pointer_view_| is null.
@@ skipping 22 matching lines @@
       kPointLifeDurationMs) {
     stationary_timer_->Stop();
     // Reset the view if the timer expires and the view was in process of fading
     // away.
     if (is_fading_away_)
       DestroyLaserPointerView();
   }
   stationary_timer_repeat_count_++;
 }
 }  // namespace ash