media: Cleanup class/struct forward declarations

media/audio/pulse/pulse_output.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.
 //
 // Creates an audio output stream based on the PulseAudio asynchronous API;
 // specifically using the pa_threaded_mainloop model.
 //
 // If the stream is successfully opened, Close() must be called before the
 // stream is deleted as Close() is responsible for ensuring resource cleanup
 // occurs.
@@ skipping 13 matching lines @@
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "media/audio/audio_io.h"
 #include "media/base/audio_parameters.h"
 
 struct pa_context;
-struct pa_operation;
 struct pa_stream;
 struct pa_threaded_mainloop;
 
 namespace media {
 class AudioManagerBase;
 
 class PulseAudioOutputStream : public AudioOutputStream {
  public:
   PulseAudioOutputStream(const AudioParameters& params,
                          const std::string& device_id,
@@ skipping 50 matching lines @@
   std::unique_ptr<AudioBus> audio_bus_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(PulseAudioOutputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_PULSE_PULSE_OUTPUT_H_