Clean up web bluetooth related code

device/bluetooth/bluez/bluetooth_remote_gatt_characteristic_bluez.h

 // 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.
 
 #ifndef DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_BLUEZ_H_
 #define DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_BLUEZ_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <map>
@@ skipping 58 matching lines @@
       const base::Closure& callback,
       const ErrorCallback& error_callback) override;
   void UnsubscribeFromNotifications(
       device::BluetoothRemoteGattDescriptor* ccc_descriptor,
       const base::Closure& callback,
       const ErrorCallback& error_callback) override;
 
  private:
   friend class BluetoothRemoteGattServiceBlueZ;
 
-  using PendingStartNotifyCall =
-      std::pair<NotifySessionCallback, ErrorCallback>;
-
   BluetoothRemoteGattCharacteristicBlueZ(
       BluetoothRemoteGattServiceBlueZ* service,
       const dbus::ObjectPath& object_path);
   ~BluetoothRemoteGattCharacteristicBlueZ() override;
 
   // bluez::BluetoothGattDescriptorClient::Observer overrides.
   void GattDescriptorAdded(const dbus::ObjectPath& object_path) override;
   void GattDescriptorRemoved(const dbus::ObjectPath& object_path) override;
   void GattDescriptorPropertyChanged(const dbus::ObjectPath& object_path,
                                      const std::string& property_name) override;
@@ skipping 45 matching lines @@
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<BluetoothRemoteGattCharacteristicBlueZ>
       weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothRemoteGattCharacteristicBlueZ);
 };
 
 }  // namespace bluez
 
 #endif  // DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_BLUEZ_H_