Expose TxPower for bluetooth devices during discovery

chromeos/dbus/bluetooth_device_client.h

Index: chromeos/dbus/bluetooth_device_client.h
diff --git a/chromeos/dbus/bluetooth_device_client.h b/chromeos/dbus/bluetooth_device_client.h
index 353fd5b53eeb82416865965b6a333e3e6e14aa98..4a0d6b4a1d0e26ae8d7fa60ca954e6f114e103b7 100644
--- a/chromeos/dbus/bluetooth_device_client.h
+++ b/chromeos/dbus/bluetooth_device_client.h
@@ -48,6 +48,10 @@ class CHROMEOS_EXPORT BluetoothDeviceClient : public DBusClient {
     // Read-only.
     dbus::Property<std::vector<std::string> > uuids;
 
+    // Transmitted power level. This field is avaliable only for LE devices
+    // that include this field in AD. Read-only.
+    dbus::Property<int16> tx_power;
+
     // Indicates that the device is currently paired. Read-only.
     dbus::Property<bool> paired;