Tablet-like power button behavior on Convertible/Tablet ChromeOS devices

chromeos/dbus/fake_power_manager_client.cc

Index: chromeos/dbus/fake_power_manager_client.cc
diff --git a/chromeos/dbus/fake_power_manager_client.cc b/chromeos/dbus/fake_power_manager_client.cc
index 6bee1ea7369bfc50732bb4412c02ed2ee6ce210e..5e212e09f9011508564d255360d1db954b8b2297 100644
--- a/chromeos/dbus/fake_power_manager_client.cc
+++ b/chromeos/dbus/fake_power_manager_client.cc
@@ -14,7 +14,10 @@ namespace chromeos {
 
 namespace {
 // Minimum power for a USB power source to be classified as AC.
-const double kUsbMinAcWatts = 24;
+constexpr double kUsbMinAcWatts = 24;
+
+// A non-zero brightness used for test.
+constexpr int kNonZeroBrightnessForTest = 10;
 }
 
 FakePowerManagerClient::FakePowerManagerClient()
@@ -137,6 +140,8 @@ void FakePowerManagerClient::SetPowerSource(const std::string& id) {
 
 void FakePowerManagerClient::SetBacklightsForcedOff(bool forced_off) {
   backlights_forced_off_ = forced_off;
+  forced_off ? SendBrightnessChanged(0, true)
+             : SendBrightnessChanged(kNonZeroBrightnessForTest, true);
 }
 
 void FakePowerManagerClient::GetBacklightsForcedOff(
@@ -196,6 +201,12 @@ void FakePowerManagerClient::UpdatePowerProperties(
   NotifyObservers();
 }
 
+void FakePowerManagerClient::SendBrightnessChanged(int level,
+                                                   bool user_initiated) {
+  for (auto& observer : observers_)
+    observer.BrightnessChanged(level, user_initiated);
+}
+
 void FakePowerManagerClient::NotifyObservers() {
   for (auto& observer : observers_)
     observer.PowerChanged(props_);