cros: Stop forcing off display when lid events are received

ash/system/power/tablet_power_button_controller_unittest.cc

Index: ash/system/power/tablet_power_button_controller_unittest.cc
diff --git a/ash/system/power/tablet_power_button_controller_unittest.cc b/ash/system/power/tablet_power_button_controller_unittest.cc
index 2805f9ff2ab5edde52f1ef9c46a89045e4b1b88b..a591130a4ff7931ef01ef601f14767029fb8dada 100644
--- a/ash/system/power/tablet_power_button_controller_unittest.cc
+++ b/ash/system/power/tablet_power_button_controller_unittest.cc
@@ -484,5 +484,24 @@ TEST_F(TabletPowerButtonControllerTest, IgnoreRepeatedPowerButtonReleases) {
   EXPECT_TRUE(GetBacklightsForcedOff());
 }
 
+// Tests that lid closed/open events can properly stop forcing off backlights.

[Daniel Erat, 2017/04/13 04:31:16]

nit: remove "can properly"

[Qiang(Joe) Xu, 2017/04/13 04:49:40]

Done.

+TEST_F(TabletPowerButtonControllerTest, LidEventsStopForcingOff) {
+  // Pressing/releasing power button to set backlights forced off.
+  PressPowerButton();
+  ReleasePowerButton();
+  EXPECT_TRUE(GetBacklightsForcedOff());

[Daniel Erat, 2017/04/13 04:31:16]

nit: ASSERT_TRUE since this isn't the thing that the test is trying to test, and
since the rest of the test will be useless if this doesn't work

[Qiang(Joe) Xu, 2017/04/13 04:49:40]

Done.

+
+  // A lid closed event is received, we should stop forcing off backlights.
+  power_manager_client_->SendLidEvent(
+      chromeos::PowerManagerClient::LidState::CLOSED, tick_clock_->NowTicks());
+  EXPECT_FALSE(GetBacklightsForcedOff());
+
+  // A lid open event is received, we should still get stopped forcing off
+  // backlights.

[Qiang(Joe) Xu, 2017/04/13 04:14:18]

For testing lid open event, generally speaking if backlights are forced off on
lid closed state. It will keep this state.

On Chrome side, only power button could do forcing off. But it should not
happen.

For testing this, we probably can expose SetDisplayForcedOff method through test
api. It should be served as testing purpose only. Shall we do that?

[Daniel Erat, 2017/04/13 04:31:16]

hmm. can you just press and release the power button again to force the
backlights off here? i agree that it's something that shouldn't happen in real
life.

[Qiang(Joe) Xu, 2017/04/13 04:49:40]

Done.

+  power_manager_client_->SendLidEvent(
+      chromeos::PowerManagerClient::LidState::OPEN, tick_clock_->NowTicks());
+  EXPECT_FALSE(GetBacklightsForcedOff());
+}
+
 }  // namespace test
 }  // namespace ash