Resuming from suspend should stop backlights forced off if they are

ash/system/chromeos/power/tablet_power_button_controller_unittest.cc

Index: ash/system/chromeos/power/tablet_power_button_controller_unittest.cc
diff --git a/ash/system/chromeos/power/tablet_power_button_controller_unittest.cc b/ash/system/chromeos/power/tablet_power_button_controller_unittest.cc
index a99fb9008e2026badf611f2cd8184761ba56b934..95123fc85eac184e4cd19f5c7fa6a11670a1a2d7 100644
--- a/ash/system/chromeos/power/tablet_power_button_controller_unittest.cc
+++ b/ash/system/chromeos/power/tablet_power_button_controller_unittest.cc
@@ -210,8 +210,10 @@ TEST_F(TabletPowerButtonControllerTest, TappingPowerButtonWhenScreenIsIdleOff) {
   EXPECT_FALSE(GetBacklightsForcedOff());
 }
 
-// Tests tapping power button when device is suspended.
-TEST_F(TabletPowerButtonControllerTest, TappingPowerButtonWhenSuspended) {
+// Tests tapping power button when device is suspended without backlights forced
+// off.
+TEST_F(TabletPowerButtonControllerTest,
+       TappingPowerButtonWhenSuspendedWithoutBacklightsForcedOff) {
   base::SimpleTestTickClock* tick_clock = new base::SimpleTestTickClock;
   // |tick_clock| owned by |tablet_controller_|.

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

nit: remove this comment; passing an std::unique_ptr makes it clear that
ownership is being transferred.

you might want to consider just making this a member and passing it in the base
class's SetUp method, since it's needed by multiple tests now.

   tablet_controller_->SetTickClockForTesting(
@@ -235,6 +237,43 @@ TEST_F(TabletPowerButtonControllerTest, TappingPowerButtonWhenSuspended) {
   tick_clock->Advance(base::TimeDelta::FromMilliseconds(1600));
   power_manager_client_->SendPowerButtonEvent(true, tick_clock->NowTicks());
   power_manager_client_->SendPowerButtonEvent(false, tick_clock->NowTicks());
+  power_manager_client_->SendBrightnessChanged(0, false);
+  EXPECT_TRUE(GetBacklightsForcedOff());
+}
+
+// Tests tapping power button when device is suspended with backlights forced
+// off.
+TEST_F(TabletPowerButtonControllerTest,
+       TappingPowerButtonWhenSuspendedWithBacklightsForcedOff) {
+  base::SimpleTestTickClock* tick_clock = new base::SimpleTestTickClock;
+  // |tick_clock| owned by |tablet_controller_|.

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

same here

+  tablet_controller_->SetTickClockForTesting(
+      std::unique_ptr<base::TickClock>(tick_clock));
+
+  PressPowerButton();
+  ReleasePowerButton();
+  power_manager_client_->SendBrightnessChanged(0, false);
+  EXPECT_TRUE(GetBacklightsForcedOff());
+  power_manager_client_->SendSuspendImminent();
+  // There is a power button pressed here, but PowerButtonEvent is sent later.
+  // Because of backlights forced off, resuming system will not resume

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

nit: s/will not resume/will not restore/

+  // brightness.
+  power_manager_client_->SendSuspendDone();
+
+  // Send the power button event after a short delay and check that it is
+  // ignored. But if backlights are forced off, stop forcing off.
+  tick_clock->Advance(base::TimeDelta::FromMilliseconds(500));
+  power_manager_client_->SendPowerButtonEvent(true, tick_clock->NowTicks());
+  power_manager_client_->SendBrightnessChanged(kNonZeroBrightness, false);
+  power_manager_client_->SendPowerButtonEvent(false, tick_clock->NowTicks());
+  EXPECT_FALSE(GetBacklightsForcedOff());
+
+  // Send the power button event after a longer delay and check that it is not
+  // ignored.
+  tick_clock->Advance(base::TimeDelta::FromMilliseconds(1600));
+  power_manager_client_->SendPowerButtonEvent(true, tick_clock->NowTicks());
+  power_manager_client_->SendPowerButtonEvent(false, tick_clock->NowTicks());
+  power_manager_client_->SendBrightnessChanged(0, false);
   EXPECT_TRUE(GetBacklightsForcedOff());
 }