Remove unused include in sequenced_worker_pool.h

media/base/media_url_demuxer.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 MEDIA_BASE_MEDIA_URL_DEMUXER_H_
 #define MEDIA_BASE_MEDIA_URL_DEMUXER_H_
 
 #include <stddef.h>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "media/base/demuxer.h"
 #include "url/gurl.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace media {
 
 // Class that saves a URL for later retrieval. To be used in conjunction with
 // the MediaPlayerRenderer.
 //
 // Its primary purpose is to act as a dummy Demuxer, when there is no need
 // for DemuxerStreams (e.g. in the MediaPlayerRenderer case). For the most part,
 // its implementation of the Demuxer are NOPs that return the default values and
 // fire any provided callbacks immediately.
 //
@@ skipping 35 matching lines @@
   MediaUrlParams params_;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaUrlDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_URL_DEMUXER_H_