device/bluetooth/bluez: add discoverable timeout adapter property

device/bluetooth/bluez/bluetooth_adapter_bluez.cc

Index: device/bluetooth/bluez/bluetooth_adapter_bluez.cc
diff --git a/device/bluetooth/bluez/bluetooth_adapter_bluez.cc b/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
index 6e304ad42ac1545cd19750f9e796cf9560f5fe1c..fdaefe32636c1ab0dcc763650364bb188c0ed41d 100644
--- a/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
+++ b/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
@@ -353,6 +353,18 @@ void BluetoothAdapterBlueZ::SetDiscoverable(
                      weak_ptr_factory_.GetWeakPtr(), callback, error_callback));
 }
 
+uint32_t BluetoothAdapterBlueZ::GetDiscoverableTimeout() const {
+  if (!IsPresent())
+    return 0;
+
+  bluez::BluetoothAdapterClient::Properties* properties =
+      bluez::BluezDBusManager::Get()
+          ->GetBluetoothAdapterClient()
+          ->GetProperties(object_path_);
+
+  return properties->discoverable_timeout.value();
+}
+
 bool BluetoothAdapterBlueZ::IsDiscovering() const {
   if (!IsPresent())
     return false;