Add CONTENT_EXPORT for content::MediaStreamAudioLevelCalculator::Level.

content/renderer/media/media_stream_audio_level_calculator.h

 // Copyright 2014 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_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
 
 namespace media {
 class AudioBus;
 }
 
 namespace content {
 
 // This class is used by the WebRtcAudioCapturer to calculate the level of the
 // audio signal. And the audio level will be eventually used by the volume
 // animation UI.
 //
 // The algorithm used by this class is the same as how it is done in
 // third_party/webrtc/voice_engine/level_indicator.cc.
 class CONTENT_EXPORT MediaStreamAudioLevelCalculator {
  public:
   // Provides thread-safe access to the current signal level.  This object is
   // intended to be passed to modules running on other threads that poll for the
   // current signal level.
-  class Level : public base::RefCountedThreadSafe<Level> {
+  class CONTENT_EXPORT Level : public base::RefCountedThreadSafe<Level> {
    public:
     float GetCurrent() const;
 
    private:
     friend class MediaStreamAudioLevelCalculator;
     friend class base::RefCountedThreadSafe<Level>;
 
     Level();
     ~Level();
 
@@ skipping 16 matching lines @@
 
  private:
   int counter_;
   float max_amplitude_;
   const scoped_refptr<Level> level_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_