Implement //device/bt changes for notifications.

device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc

Index: device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc
diff --git a/device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc b/device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc
index 95805221ad57e4d3f88f0bf81d690e9bf88a8a1a..08511ea1928b826b9dfc48ee703fa932be6de672 100644
--- a/device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc
+++ b/device/bluetooth/dbus/bluetooth_gatt_characteristic_delegate_wrapper.cc
@@ -31,8 +31,12 @@ void BluetoothGattCharacteristicDelegateWrapper::SetValue(
       service_, characteristic_, value, 0, callback, error_callback);
 }
 
-void BluetoothGattCharacteristicDelegateWrapper::StartNotifications() {}
+void BluetoothGattCharacteristicDelegateWrapper::StartNotifications() {
+  service_->GetDelegate()->OnNotificationsStart(service_, characteristic_);
+}
 
-void BluetoothGattCharacteristicDelegateWrapper::StopNotifications() {}
+void BluetoothGattCharacteristicDelegateWrapper::StopNotifications() {
+  service_->GetDelegate()->OnNotificationsStop(service_, characteristic_);
+}
 
 }  // namespace bluez