remoting: Cleanup class/struct fwd declarations

remoting/host/win/worker_process_launcher.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 REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_
 #define REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer/timer.h"
 #include "base/win/object_watcher.h"
 #include "base/win/scoped_handle.h"
 #include "net/base/backoff_entry.h"
 
 namespace base {
-class SingleThreadTaskRunner;
 class TimeDelta;
 } // namespace base
 
 namespace IPC {
 class Message;
 } // namespace IPC
 
 namespace tracked_objects {
 class Location;
 }  // namespace tracked_objects
@@ skipping 129 matching lines @@
 
   // The handle of the worker process, if launched.
   base::win::ScopedHandle worker_process_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkerProcessLauncher);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_