bluetooth: connectGATT and receive WebBluetoothGATTRemoteServer from embedder.

Source/modules/bluetooth/BluetoothGATTRemoteServer.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-BluetoothGATTRemoteServer
 
 // Implement BluetoothGATTRemoteServer interface: https://crbug.com/476735
 
 [
     GarbageCollected,
     RuntimeEnabled=Bluetooth,
 ] interface BluetoothGATTRemoteServer
 // Implement ServiceEventHandlers interface: http://crbug.com/421670
 // : ServiceEventHandlers 
 {
   // readonly attribute BluetoothDevice      device;
-  // readonly attribute boolean              connected;
+    readonly attribute boolean              connected;
   // void                                    disconnect ();
   // Promise<BluetoothGATTService>           getPrimaryService (BluetoothServiceUuid service);
   // Promise<sequence<BluetoothGATTService>> getPrimaryServices (optional BluetoothServiceUuid service);
 };