ash: Add one second grace period For LockScreenIfRequired

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"
 
 namespace ash {
 
 namespace {
 
 // Amount of time the power button must be held to start the pre-shutdown
 // animation when in tablet mode.
 constexpr int kShutdownTimeoutMs = 1000;
 
+// Amount of time that locking screen needs to be waited to start the actual

[Daniel Erat, 2017/01/11 23:09:06]

this comment is a bit confusing. is it more like:

"Amount of time that power button must be held before screen is locked."

?

[Qiang(Joe) Xu, 2017/01/12 00:04:45]

That is not right. This cl is about: "after set display off, and wait 1s, then
perform locking screen action if required; but if there is a
SetDisplayOff(false) call before lock_screen_timer_ times out, stop the timer so
the OnLockScreenTimeout will not get called".

+// locking screen.
+constexpr int kLockScreenTimeoutMs = 1000;
+
 // Amount of time since last SuspendDone() that power button event needs to be
 // ignored.
 constexpr int kIgnorePowerButtonAfterResumeMs = 2000;
 
 // Returns true if device is a convertible/tablet device or has
 // kAshEnableTouchViewTesting in test, otherwise false.
 bool IsTabletModeSupported() {
   MaximizeModeController* maximize_mode_controller =
       WmShell::Get()->maximize_mode_controller();
   return maximize_mode_controller &&
@@ skipping 19 matching lines @@
 bool TabletPowerButtonController::TestApi::ShutdownTimerIsRunning() const {
   return controller_->shutdown_timer_.IsRunning();
 }
 
 void TabletPowerButtonController::TestApi::TriggerShutdownTimeout() {
   DCHECK(ShutdownTimerIsRunning());
   controller_->OnShutdownTimeout();
   controller_->shutdown_timer_.Stop();
 }
 
+bool TabletPowerButtonController::TestApi::LockScreenTimerIsRunning() const {
+  return controller_->lock_screen_timer_.IsRunning();
+}
+
+void TabletPowerButtonController::TestApi::TriggerLockScreenTimeout() {
+  DCHECK(LockScreenTimerIsRunning());
+  controller_->OnLockScreenTimeout();
+  controller_->lock_screen_timer_.Stop();
+}
+
 TabletPowerButtonController::TabletPowerButtonController(
     LockStateController* controller)
     : tick_clock_(new base::DefaultTickClock()),
       last_resume_time_(base::TimeTicks()),
       force_off_on_button_up_(true),
       controller_(controller),
       weak_ptr_factory_(this) {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(
       this);
   WmShell::Get()->AddShellObserver(this);
@@ skipping 122 matching lines @@
   backlights_forced_off_ = forced_off;
 
   ShellDelegate* delegate = WmShell::Get()->delegate();
   delegate->SetTouchscreenEnabledInPrefs(!forced_off,
                                          true /* use_local_state */);
   delegate->UpdateTouchscreenStatusFromPrefs();
 
   // Send an a11y alert.
   WmShell::Get()->accessibility_delegate()->TriggerAccessibilityAlert(
       forced_off ? A11Y_ALERT_SCREEN_OFF : A11Y_ALERT_SCREEN_ON);
+
+  // Reset |lock_screen_timer_| when display is not set to forced off since

[Daniel Erat, 2017/01/11 23:09:06]

this doesn't feel like the right place for this code. the method is named
SetDisplayForcedOff, so stopping the screen-lock timer feels like an unexpected
side effect. i'd recommend instead calling lock_screen_timer_.Stop() directly in
all the places where you call SetDisplayForcedOff(false).

with that said, i'm not sure that it makes sense to stop the timer if a key is
pressed or the mouse is used while the power button is held. maybe i'm
misunderstanding this, though. what's the use case that you're trying to handle
here?

[Qiang(Joe) Xu, 2017/01/12 00:04:45]

Agree that we should put it in all the places where we call
SetDisplayForcedOff(false).

As explained in the above, so the quick "two power button tapping /  power
button tapping + keyboard event / power button tapping + mouse event" will not
turn out as locked screen with display on.

+  // under this case, |lock_screen_timer_| should not timeout.

[Daniel Erat, 2017/01/11 23:09:06]

nit: s/timeout/time out/ ("time out" is verb, "timeout" is noun)

[Qiang(Joe) Xu, 2017/01/12 00:04:45]

done by removing.

+  if (!forced_off)
+    lock_screen_timer_.Stop();

[Qiang(Joe) Xu, 2017/01/11 22:17:06]

Moved here: since besides two quick power button tapping, power button tap +
keyboard event, power button + mouse event should also not lock screen.

 }
 
 void TabletPowerButtonController::GetInitialBacklightsForcedOff() {
   chromeos::DBusThreadManager::Get()
       ->GetPowerManagerClient()
       ->GetBacklightsForcedOff(base::Bind(
           &TabletPowerButtonController::OnGotInitialBacklightsForcedOff,
           weak_ptr_factory_.GetWeakPtr()));
 }
 
@@ skipping 12 matching lines @@
   controller_->StartShutdownAnimation();
 }
 
 void TabletPowerButtonController::LockScreenIfRequired() {
   SessionStateDelegate* session_state_delegate =
       WmShell::Get()->GetSessionStateDelegate();
   if (session_state_delegate->ShouldLockScreenAutomatically() &&
       session_state_delegate->CanLockScreen() &&
       !session_state_delegate->IsUserSessionBlocked() &&
       !controller_->LockRequested()) {
-    session_state_delegate->LockScreen();
+    StartLockScreenTimer();
   }
 }
 
+void TabletPowerButtonController::StartLockScreenTimer() {
+  lock_screen_timer_.Start(

[Daniel Erat, 2017/01/11 23:09:06]

mind moving this into LockScreenIfRequired since it's a single statement and
looks like it's only called from a single place?

[Qiang(Joe) Xu, 2017/01/12 00:04:45]

Done.

+      FROM_HERE, base::TimeDelta::FromMilliseconds(kLockScreenTimeoutMs), this,
+      &TabletPowerButtonController::OnLockScreenTimeout);
+}
+
+void TabletPowerButtonController::OnLockScreenTimeout() {
+  WmShell::Get()->GetSessionStateDelegate()->LockScreen();
+}
+
 }  // namespace ash