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

ash/system/power/tablet_power_button_controller.cc

Index: ash/system/power/tablet_power_button_controller.cc
diff --git a/ash/system/power/tablet_power_button_controller.cc b/ash/system/power/tablet_power_button_controller.cc
index a2b252809570dbedee17d42ef95d5f520d6b6d55..9282ca3e1dacddf994fd64bf00807aa898f4f569 100644
--- a/ash/system/power/tablet_power_button_controller.cc
+++ b/ash/system/power/tablet_power_button_controller.cc
@@ -55,6 +55,15 @@ bool IsTabletModeActive() {
          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(
@@ -221,10 +230,7 @@ void TabletPowerButtonController::SetDisplayForcedOff(bool forced_off) {
       ->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(
@@ -242,6 +248,7 @@ void TabletPowerButtonController::GetInitialBacklightsForcedOff() {
 void TabletPowerButtonController::OnGotInitialBacklightsForcedOff(
     bool is_forced_off) {
   backlights_forced_off_ = is_forced_off;
+  UpdateTouchscreenStatus(!backlights_forced_off_);
 }
 
 void TabletPowerButtonController::StartShutdownTimer() {