cros: Stop forcing off display when lid events are received

ash/system/power/tablet_power_button_controller_unittest.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/power/tablet_power_button_controller.h"
 
 #include <memory>
 
 #include "ash/ash_switches.h"
 #include "ash/public/cpp/config.h"
@@ skipping 466 matching lines @@
   EXPECT_FALSE(GetBacklightsForcedOff());
 
   // Test that after another long duration, backlights should be forced off.
   tick_clock_->Advance(base::TimeDelta::FromMilliseconds(800));
   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 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