bluetooth: Blink side implementation of getPrimaryService

Source/modules/bluetooth/BluetoothGATTService.idl

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // https://webbluetoothcg.github.io/web-bluetooth/#idl-def-bluetoothgattservice
 
 // Implement BluetoothGATTService interface: https://crbug.com/483342
 
 typedef DOMString UUID;
 
 [
     GarbageCollected,
     RuntimeEnabled=WebBluetooth,
 ] interface BluetoothGATTService { // : ServiceEventHandlers {
-    // readonly    attribute UUID            uuid;
-    // readonly    attribute boolean         isPrimary;
-    // readonly    attribute DOMString       instanceID;
+    readonly    attribute UUID            uuid;
+    readonly    attribute boolean         isPrimary;
     // readonly    attribute BluetoothDevice device;
     // Promise<BluetoothGATTCharacteristic>           getCharacteristic(BluetoothCharacteristicUUID characteristic);
     // Promise<sequence<BluetoothGATTCharacteristic>> getCharacteristics(optional BluetoothCharacteristicUUID characteristic);
     // Promise<BluetoothGATTService>                  getIncludedService(BluetoothServiceUUID service);
     // Promise<sequence<BluetoothGATTService>>        getIncludedServices(optional BluetoothServiceUUID service);
 };