Revert r95841 due to failing media_unittests on linux_shared bot.

media/filters/null_audio_renderer.h

 // Copyright (c) 2011 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_FILTERS_NULL_AUDIO_RENDERER_H_
 #define MEDIA_FILTERS_NULL_AUDIO_RENDERER_H_
 
 // NullAudioRenderer effectively uses an extra thread to "throw away" the
 // audio data at a rate resembling normal playback speed.  It's just like
 // decoding to /dev/null!
 //
 // NullAudioRenderer can also be used in situations where the client has no
 // audio device or we haven't written an audio implementation for a particular
 // platform yet.
 
 #include <deque>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/platform_thread.h"
 #include "media/base/buffers.h"
 #include "media/base/filters.h"
 #include "media/filters/audio_renderer_base.h"
 
 namespace media {
 
-class MEDIA_EXPORT NullAudioRenderer
+class NullAudioRenderer
     : public AudioRendererBase,
       public base::PlatformThread::Delegate {
  public:
   NullAudioRenderer();
   virtual ~NullAudioRenderer();
 
   // AudioRenderer implementation.
   virtual void SetVolume(float volume);
 
   // PlatformThread::Delegate implementation.
@@ skipping 18 matching lines @@
 
   // Shutdown flag.
   bool shutdown_;
 
   DISALLOW_COPY_AND_ASSIGN(NullAudioRenderer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_NULL_AUDIO_RENDERER_H_