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

ash/system/power/tablet_power_button_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/system/power/tablet_power_button_controller.h"
 
 #include "ash/accessibility_delegate.h"
 #include "ash/session/session_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
@@ skipping 37 matching lines @@
 }
 
 // Returns true if device is currently in tablet/maximize mode, otherwise false.
 bool IsTabletModeActive() {
   MaximizeModeController* maximize_mode_controller =
       Shell::Get()->maximize_mode_controller();
   return maximize_mode_controller &&
          maximize_mode_controller->IsMaximizeModeWindowManagerEnabled();
 }
 
+// Update Touchscreen status based on the provided |local_pref_enabled|, which

[Daniel Erat, 2017/05/03 00:48:46]

nit: s/Touchscreen/touchscreen/

[Qiang(Joe) Xu, 2017/05/03 03:14:22]

Done.

+// is a reverse state of |backlights_forced_off_|.

[Daniel Erat, 2017/05/03 00:48:46]

instead of referring to backlights_forced_off_ (which doesn't really make sense
in this anon function), how about something like this?

  // Enables or disables the touchscreen, also writing its state
  // to a pref in local state. The touchscreen is disabled when
  // backlights are forced off.

alternately, would it be cleaner for this to just be a private non-static method
in TabletPowerButtonController that doesn't take a param and instead just uses
backlights_forced_off_ to figure out what it should do?

[Qiang(Joe) Xu, 2017/05/03 03:14:22]

done by moving this to private method. That is better. Thanks!

+void UpdateTouchscreenStatus(bool local_pref_enabled) {

[Daniel Erat, 2017/05/03 00:48:46]

local_pref_enabled is a bit confusing. can you rename it to just be "enabled"?

[Qiang(Joe) Xu, 2017/05/03 03:14:22]

Done.

+  ShellDelegate* delegate = Shell::Get()->shell_delegate();
+  delegate->SetTouchscreenEnabledInPrefs(local_pref_enabled,
+                                         true /* use_local_state */);
+  delegate->UpdateTouchscreenStatusFromPrefs();
+}
+
 }  // namespace
 
 TabletPowerButtonController::TestApi::TestApi(
     TabletPowerButtonController* controller)
     : controller_(controller) {}
 
 TabletPowerButtonController::TestApi::~TestApi() {}
 
 bool TabletPowerButtonController::TestApi::ShutdownTimerIsRunning() const {
   return controller_->shutdown_timer_.IsRunning();
@@ skipping 145 matching lines @@
 
 void TabletPowerButtonController::SetDisplayForcedOff(bool forced_off) {
   if (backlights_forced_off_ == forced_off)
     return;
 
   // Set the display and keyboard backlights (if present) to |forced_off|.
   chromeos::DBusThreadManager::Get()
       ->GetPowerManagerClient()
       ->SetBacklightsForcedOff(forced_off);
   backlights_forced_off_ = forced_off;
 

[Daniel Erat, 2017/05/03 00:48:46]

nit: delete blank line?

[Qiang(Joe) Xu, 2017/05/03 03:14:22]

Done.

-  ShellDelegate* delegate = Shell::Get()->shell_delegate();
-  delegate->SetTouchscreenEnabledInPrefs(!forced_off,
-                                         true /* use_local_state */);
-  delegate->UpdateTouchscreenStatusFromPrefs();
+  UpdateTouchscreenStatus(!backlights_forced_off_);
 
   // Send an a11y alert.
   Shell::Get()->accessibility_delegate()->TriggerAccessibilityAlert(
       forced_off ? A11Y_ALERT_SCREEN_OFF : A11Y_ALERT_SCREEN_ON);
 }
 
 void TabletPowerButtonController::GetInitialBacklightsForcedOff() {
   chromeos::DBusThreadManager::Get()
       ->GetPowerManagerClient()
       ->GetBacklightsForcedOff(base::Bind(
           &TabletPowerButtonController::OnGotInitialBacklightsForcedOff,
           weak_ptr_factory_.GetWeakPtr()));
 }
 
 void TabletPowerButtonController::OnGotInitialBacklightsForcedOff(
     bool is_forced_off) {
   backlights_forced_off_ = is_forced_off;
+  UpdateTouchscreenStatus(!backlights_forced_off_);
 }
 
 void TabletPowerButtonController::StartShutdownTimer() {
   base::TimeDelta timeout = base::TimeDelta::FromMilliseconds(
       screen_off_when_power_button_down_ ? kShutdownWhenScreenOffTimeoutMs
                                          : kShutdownWhenScreenOnTimeoutMs);
   shutdown_timer_.Start(FROM_HERE, timeout, this,
                         &TabletPowerButtonController::OnShutdownTimeout);
 }
 
 void TabletPowerButtonController::OnShutdownTimeout() {
   controller_->StartShutdownAnimation();
 }
 
 void TabletPowerButtonController::LockScreenIfRequired() {
   SessionController* session_controller = Shell::Get()->session_controller();
   if (session_controller->ShouldLockScreenAutomatically() &&
       session_controller->CanLockScreen() &&
       !session_controller->IsUserSessionBlocked() &&
       !controller_->LockRequested()) {
     session_controller->LockScreen();
   }
 }
 
 }  // namespace ash