Enabled/disable touch screen in TabletPowerButtonController

ash/system/chromeos/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/chromeos/power/tablet_power_button_controller.h"
 
 #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"
 #include "ash/wm/lock_state_controller.h"
 #include "base/time/default_tick_clock.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "ui/events/devices/input_device_manager.h"
 #include "ui/events/devices/stylus_state.h"
 #include "ui/events/event.h"
 
@@ skipping 47 matching lines @@
 TabletPowerButtonController::TabletPowerButtonController(
     LockStateController* controller)
     : tick_clock_(new base::DefaultTickClock()),
       last_resume_time_(base::TimeTicks()),
       controller_(controller),
       weak_ptr_factory_(this) {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(
       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(
       this);
 }
 
 bool TabletPowerButtonController::ShouldHandlePowerButtonEvents() const {
   return IsTabletModeSupported();
 }
 
 void TabletPowerButtonController::OnPowerButtonEvent(
     bool down,
     const base::TimeTicks& timestamp) {
   // When the system resumes in response to the power button being pressed,
   // Chrome receives powerd's SuspendDone signal and notification that the
   // backlight has been turned back on before seeing the power button events
   // that woke the system. Ignore events just after resuming to ensure that we
   // don't turn the screen off in response to the events.
   if (timestamp - last_resume_time_ <=
       base::TimeDelta::FromMilliseconds(kIgnorePowerButtonAfterResumeMs)) {
     return;
   }
 
   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();
       }
     }
     screen_off_when_power_button_down_ = false;
 
     // When power button is released, cancel shutdown animation whenever it is
     // still cancellable.
     if (controller_->CanCancelShutdownAnimation())
       controller_->CancelShutdownAnimation();
   }
 }
 
 void TabletPowerButtonController::PowerManagerRestarted() {
   chromeos::DBusThreadManager::Get()
       ->GetPowerManagerClient()
       ->SetBacklightsForcedOff(backlights_forced_off_);
 }
 
 void TabletPowerButtonController::BrightnessChanged(int level,
                                                     bool user_initiated) {
   brightness_level_is_zero_ = level == 0;
 }
 
 void TabletPowerButtonController::SuspendDone(
     const base::TimeDelta& sleep_duration) {
   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().
   if (event->key_code() == ui::VKEY_POWER)
     return;
 
   if (!IsTabletModeActive() && backlights_forced_off_)
-    SetBacklightsForcedOff(false);
+    SetDisplayForcedOff(false);
 }
 
 void TabletPowerButtonController::OnMouseEvent(ui::MouseEvent* event) {
   ui::EventPointerType pointer_type = event->pointer_details().pointer_type;
 
   if (pointer_type != ui::EventPointerType::POINTER_TYPE_MOUSE ||
       (event->flags() & ui::EF_IS_SYNTHESIZED)) {
     return;
   }
 
   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);
   }
 }
 
 void TabletPowerButtonController::SetTickClockForTesting(
     std::unique_ptr<base::TickClock> tick_clock) {
   DCHECK(tick_clock);
   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);
 }
 
 void TabletPowerButtonController::GetInitialBacklightsForcedOff() {
   chromeos::DBusThreadManager::Get()
       ->GetPowerManagerClient()
       ->GetBacklightsForcedOff(base::Bind(
           &TabletPowerButtonController::OnGotInitialBacklightsForcedOff,
           weak_ptr_factory_.GetWeakPtr()));
 }
@@ skipping 18 matching lines @@
       WmShell::Get()->GetSessionStateDelegate();
   if (session_state_delegate->ShouldLockScreenAutomatically() &&
       session_state_delegate->CanLockScreen() &&
       !session_state_delegate->IsUserSessionBlocked() &&
       !controller_->LockRequested()) {
     session_state_delegate->LockScreen();
   }
 }
 
 }  // namespace ash