Fix "unused variable" warnings.

tools/android/forwarder2/host_controller.h

 // Copyright (c) 2012 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 TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_
 #define TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 40 matching lines @@
   void Start();
 
   int adb_port() const { return adb_port_; }
 
   int device_port() const { return device_port_; }
 
  private:
   HostController(int device_port,
                  int host_port,
                  int adb_port,
-                 int exit_notifier_fd,
                  const ErrorCallback& error_callback,
                  std::unique_ptr<Socket> adb_control_socket,
                  std::unique_ptr<PipeNotifier> delete_controller_notifier);
 
   void ReadNextCommandSoon();
   void ReadCommandOnInternalThread();
 
   void StartForwarder(std::unique_ptr<Socket> host_server_data_socket);
 
   // Note that this gets also called when ~HostController() is invoked.
   void OnInternalThreadError();
 
   void UnmapPortOnDevice();
 
   SelfDeleterHelper<HostController> self_deleter_helper_;
   const int device_port_;
   const int host_port_;
   const int adb_port_;
-  // Used to notify the controller when the process is killed.
-  const int global_exit_notifier_fd_;
   std::unique_ptr<Socket> adb_control_socket_;
   // Used to cancel the pending blocking IO operations when the host controller
   // instance is deleted.
   std::unique_ptr<PipeNotifier> delete_controller_notifier_;
   // Task runner used for deletion set at deletion time (i.e. the object is
   // deleted on the same thread it is created on).
   const scoped_refptr<base::SingleThreadTaskRunner> deletion_task_runner_;
   base::Thread thread_;
   ForwardersManager forwarders_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(HostController);
 };
 
 }  // namespace forwarder2
 
 #endif  // TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_