Remove unused include in sequenced_worker_pool.h

components/pairing/bluetooth_host_pairing_controller.h

 // Copyright 2014 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 COMPONENTS_PAIRING_BLUETOOTH_HOST_PAIRING_CONTROLLER_H_
 #define COMPONENTS_PAIRING_BLUETOOTH_HOST_PAIRING_CONTROLLER_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "components/pairing/host_pairing_controller.h"
 #include "components/pairing/proto_decoder.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "device/bluetooth/bluetooth_socket.h"
 #include "device/hid/input_service_linux.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace device {
 class BluetoothAdapter;
 }
 
 namespace net {
 class IOBuffer;
 }
 
 namespace pairing_chromeos {
 
@@ skipping 111 matching lines @@
   base::ThreadChecker thread_checker_;
   base::ObserverList<Observer> observers_;
   base::WeakPtrFactory<BluetoothHostPairingController> ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothHostPairingController);
 };
 
 }  // namespace pairing_chromeos
 
 #endif  // COMPONENTS_PAIRING_BLUETOOTH_HOST_PAIRING_CONTROLLER_H_