Remove unused include in sequenced_worker_pool.h

content/public/browser/browser_thread.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 CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_
 #define CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/task_runner_util.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 
 namespace base {
 class MessageLoop;
 class SequencedWorkerPool;
 class Thread;
 }
@@ skipping 273 matching lines @@
  private:
   friend class BrowserThreadImpl;
 
   BrowserThread() {}
   DISALLOW_COPY_AND_ASSIGN(BrowserThread);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_