bluetooth: android: Implement Characteristic GetIdentifier, fix Service IDs too.

device/bluetooth/bluetooth_gatt_service.h

Index: device/bluetooth/bluetooth_gatt_service.h
diff --git a/device/bluetooth/bluetooth_gatt_service.h b/device/bluetooth/bluetooth_gatt_service.h
index 58464fcd3866df6dac620ba4360212487c17b903..35ec16de056bd2e2ac52688683d1159d9103e1e5 100644
--- a/device/bluetooth/bluetooth_gatt_service.h
+++ b/device/bluetooth/bluetooth_gatt_service.h
@@ -159,7 +159,7 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothGattService {
   // Identifier used to uniquely identify a GATT service object. This is
   // different from the service UUID: while multiple services with the same UUID
   // can exist on a Bluetooth device, the identifier returned from this method
-  // is unique among all services of a device. The contents of the identifier
+  // is unique among all services on the adapter. The contents of the identifier
   // are platform specific.
   virtual std::string GetIdentifier() const = 0;