Resuming from suspend should stop backlights forced off if they are

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/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
@@ skipping 76 matching lines @@
 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.
+  // that woke the system. If backlights are forced off, stop forcing off

[Daniel Erat, 2016/12/02 00:58:27]

nit: i'd move this "If ..." part down just before the "if (down &&
backlights_forced_off_)" line, since that's what it's referring to.

+  // because resuming system doesn't handle this, otherwise 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)) {
+    if (down && backlights_forced_off_)
+      SetBacklightsForcedOff(false);

[Qiang(Joe) Xu, 2016/12/02 01:06:38]

Hi, just want to mention here, the long pressed shutdown white animation is
missing here because the following StartShutdownTimer is ignored. I need to
think of fixing it. It can be fixed within this cl or separately.

[Daniel Erat, 2016/12/02 01:10:26]

are you just saying power button down events that wake the system from suspend
won't trigger shutdown? i think that that's the correct behavior, actually. the
non-tablet power button controller does something similar: we don't lock or shut
down when the power button is pressed while the screen is off.

     return;
   }
 
   if (down) {
     screen_off_when_power_button_down_ = brightness_level_is_zero_;
     SetBacklightsForcedOff(false);
     StartShutdownTimer();
   } else {
     if (shutdown_timer_.IsRunning()) {
       shutdown_timer_.Stop();
@@ skipping 104 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