Enabled/disable touch screen in TabletPowerButtonController

ash/system/chromeos/power/tablet_power_button_controller.cc

Index: ash/system/chromeos/power/tablet_power_button_controller.cc
diff --git a/ash/system/chromeos/power/tablet_power_button_controller.cc b/ash/system/chromeos/power/tablet_power_button_controller.cc
index 06d9efae2292990d999ea471bae6c94bf3424912..041072cab7d992c01e07c41dbdb8bbc127c1e594 100644
--- a/ash/system/chromeos/power/tablet_power_button_controller.cc
+++ b/ash/system/chromeos/power/tablet_power_button_controller.cc
@@ -6,6 +6,7 @@
 
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
+#include "ash/common/shell_delegate.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/shell.h"
@@ -73,11 +74,13 @@ TabletPowerButtonController::TabletPowerButtonController(
       this);
   ui::InputDeviceManager::GetInstance()->AddObserver(this);
   Shell::GetInstance()->PrependPreTargetHandler(this);
+  WmShell::Get()->AddShellObserver(this);
 
   GetInitialBacklightsForcedOff();
 }
 
 TabletPowerButtonController::~TabletPowerButtonController() {
+  WmShell::Get()->RemoveShellObserver(this);
   Shell::GetInstance()->RemovePreTargetHandler(this);
   ui::InputDeviceManager::GetInstance()->RemoveObserver(this);
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(
@@ -103,13 +106,13 @@ void TabletPowerButtonController::OnPowerButtonEvent(
 
   if (down) {
     screen_off_when_power_button_down_ = brightness_level_is_zero_;
-    SetBacklightsForcedOff(false);
+    SetDisplayForcedOff(false);
     StartShutdownTimer();
   } else {
     if (shutdown_timer_.IsRunning()) {
       shutdown_timer_.Stop();
       if (!screen_off_when_power_button_down_) {
-        SetBacklightsForcedOff(true);
+        SetDisplayForcedOff(true);
         LockScreenIfRequired();
       }
     }
@@ -138,6 +141,13 @@ void TabletPowerButtonController::SuspendDone(
   last_resume_time_ = tick_clock_->NowTicks();
 }
 
+void TabletPowerButtonController::OnLoginStateChanged(LoginStatus status) {
+  bool touch_screen_enabled = !backlights_forced_off_;
+  // Sync the touch screen enabled state when there is a login status change as
+  // they might differ with the current display state.
+  WmShell::Get()->delegate()->SetTouchscreenEnabled(touch_screen_enabled);

[Daniel Erat, 2016/11/30 22:58:07]

is there a possibility of a race here? is it guaranteed that the profile's state
will be applied before this method is called and the forced-off state is
applied?

[Qiang(Joe) Xu, 2016/12/02 17:42:52]

done by removing this.

+}
+
 void TabletPowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
   // Ignore key events generated by the power button since power button activity
   // is already handled by OnPowerButtonEvent().
@@ -145,7 +155,7 @@ void TabletPowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
     return;
 
   if (!IsTabletModeActive() && backlights_forced_off_)
-    SetBacklightsForcedOff(false);
+    SetDisplayForcedOff(false);
 }
 
 void TabletPowerButtonController::OnMouseEvent(ui::MouseEvent* event) {
@@ -157,13 +167,13 @@ void TabletPowerButtonController::OnMouseEvent(ui::MouseEvent* event) {
   }
 
   if (!IsTabletModeActive() && backlights_forced_off_)
-    SetBacklightsForcedOff(false);
+    SetDisplayForcedOff(false);
 }
 
 void TabletPowerButtonController::OnStylusStateChanged(ui::StylusState state) {
   if (IsTabletModeSupported() && state == ui::StylusState::REMOVED &&
       backlights_forced_off_) {
-    SetBacklightsForcedOff(false);
+    SetDisplayForcedOff(false);
   }
 }
 
@@ -173,17 +183,23 @@ void TabletPowerButtonController::SetTickClockForTesting(
   tick_clock_ = std::move(tick_clock);
 }
 
-void TabletPowerButtonController::SetBacklightsForcedOff(bool forced_off) {
+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;
 
+  bool touch_screen_enabled = !forced_off;
+  // Set the enabled state of touchscreen to |touch_screen_enabled|.

[Daniel Erat, 2016/11/30 22:58:07]

remove this comment; it's obvious from the code

[Qiang(Joe) Xu, 2016/12/02 17:42:51]

Done.

+  WmShell* wm_shell = WmShell::Get();
+  wm_shell->delegate()->SetTouchscreenEnabled(touch_screen_enabled);
+
   // Send an a11y alert.
-  WmShell::Get()->accessibility_delegate()->TriggerAccessibilityAlert(
+  wm_shell->accessibility_delegate()->TriggerAccessibilityAlert(
       forced_off ? A11Y_ALERT_SCREEN_OFF : A11Y_ALERT_SCREEN_ON);
 }