Use the powerd-provided value for low-power adapter notifications.

BUG=b:160854398

Change-Id: Ie75213a865d608835f93506c7f2b21c264880bde
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417670Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Sam McNally <sammc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810466}

ash/system/power/power_notification_controller_unittest.cc

@@ -271,6 +271,7 @@ TEST_F(PowerNotificationControllerTest,
       power_manager::PowerSupplyProperties_ExternalPower_AC);
   ac_connected.set_battery_state(
       power_manager::PowerSupplyProperties_BatteryState_NOT_PRESENT);
+  ac_connected.set_preferred_minimum_external_power(60.0);
   EXPECT_FALSE(MaybeShowUsbChargerNotification(ac_connected));
   EXPECT_EQ(0, message_center()->add_count());
   EXPECT_EQ(0, message_center()->remove_count());
@@ -281,6 +282,7 @@ TEST_F(PowerNotificationControllerTest,
       power_manager::PowerSupplyProperties_ExternalPower_USB);
   usb_connected.set_battery_state(
       power_manager::PowerSupplyProperties_BatteryState_NOT_PRESENT);
+  usb_connected.set_preferred_minimum_external_power(60.0);
   EXPECT_TRUE(MaybeShowUsbChargerNotification(usb_connected));
   EXPECT_EQ(1, message_center()->add_count());
   EXPECT_EQ(0, message_center()->remove_count());

ash/system/power/power_status.cc

@@ -486,8 +486,7 @@ base::string16 PowerStatus::GetInlinedStatusString() const {
 }
 
 double PowerStatus::GetPreferredMinimumPower() const {
-  // TODO(b/160854398): Return the value from the proto once it's ready.
-  return 60.0;
+  return proto_.preferred_minimum_external_power();
 }
 
 PowerStatus::PowerStatus() {

ash/system/power/power_status_unittest.cc

@@ -283,4 +283,14 @@ TEST_F(PowerStatusTest, MissingBatteryTimeEstimates) {
   EXPECT_FALSE(time) << *time << " returned despite negative estimate";
 }
 
+TEST_F(PowerStatusTest, PreferredMinimumExternalPower) {
+  PowerSupplyProperties prop;
+  prop.set_external_power(PowerSupplyProperties::USB);
+  prop.set_battery_state(PowerSupplyProperties::NOT_PRESENT);
+  prop.set_preferred_minimum_external_power(23.45);
+  power_status_->SetProtoForTesting(prop);
+
+  EXPECT_EQ(23.45, power_status_->GetPreferredMinimumPower());
+}
+
 }  // namespace ash