Implement DBus changes needed for notifications.

device/bluetooth/dbus/bluetooth_gatt_descriptor_service_provider_impl.cc

 // Copyright 2016 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.
 
 #include "device/bluetooth/dbus/bluetooth_gatt_descriptor_service_provider_impl.h"
 
 #include <cstddef>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 23 matching lines @@
     : origin_thread_id_(base::PlatformThread::CurrentId()),
       uuid_(uuid),
       flags_(flags),
       bus_(bus),
       delegate_(std::move(delegate)),
       object_path_(object_path),
       characteristic_path_(characteristic_path),
       weak_ptr_factory_(this) {
   VLOG(1) << "Created Bluetooth GATT characteristic descriptor: "
           << object_path.value() << " UUID: " << uuid;
-
-  // If we have a null bus, this means that this is being initialized for a
-  // test, hence we shouldn't do any other setup.
   if (!bus_)
     return;
 
   DCHECK(delegate_);
   DCHECK(!uuid_.empty());
   DCHECK(object_path_.IsValid());
   DCHECK(characteristic_path_.IsValid());
   DCHECK(base::StartsWith(object_path_.value(),
                           characteristic_path_.value() + "/",
                           base::CompareCase::SENSITIVE));
@@ skipping 349 matching lines @@
           method_call, kErrorFailed, "Failed to get/set descriptor value.");
   response_sender.Run(std::move(error_response));
 }
 
 const dbus::ObjectPath&
 BluetoothGattDescriptorServiceProviderImpl::object_path() const {
   return object_path_;
 }
 
 }  // namespace bluez