cros: Update touchscreen status with backlights forced off state during start

ash/wm/power_button_controller.cc

 // 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.
 
 #include "ash/wm/power_button_controller.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/ash_switches.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/session/session_controller.h"
@@ skipping 178 matching lines @@
   internal_display_off_and_external_display_on_ =
       internal_display_off && external_display_on;
 }
 
 void PowerButtonController::PowerButtonEventReceived(
     bool down,
     const base::TimeTicks& timestamp) {
   OnPowerButtonEvent(down, timestamp);
 }
 
+void PowerButtonController::ResetTabletPowerButtonControllerForTest() {
+  tablet_controller_.reset(
+      new TabletPowerButtonController(lock_state_controller_));
+}
+
 }  // namespace ash