Redesign the copresence audio handlers.

components/copresence/mediums/audio/audio_recorder.h

Index: components/copresence/mediums/audio/audio_recorder.h
diff --git a/components/copresence/mediums/audio/audio_recorder.h b/components/copresence/mediums/audio/audio_recorder.h
index 5c68eca1808b5c064be2f6426514559186b0adc8..4240fb361d0c8b4c352e4c62842f014d3bf6345b 100644
--- a/components/copresence/mediums/audio/audio_recorder.h
+++ b/components/copresence/mediums/audio/audio_recorder.h
@@ -28,12 +28,12 @@ namespace copresence {
 class AudioRecorder : public media::AudioInputStream::AudioInputCallback,
                       public media::AudioConverter::InputCallback {
  public:
-  typedef base::Callback<void(const std::string&)> DecodeSamplesCallback;
+  typedef base::Callback<void(const std::string&)> RecordedSamplesCallback;
 
-  explicit AudioRecorder(const DecodeSamplesCallback& decode_callback);
+  AudioRecorder();
 
   // Initializes the object. Do not use this object before calling this method.
-  virtual void Initialize();
+  virtual void Initialize(const RecordedSamplesCallback& decode_callback);
 
   virtual void Record();
   virtual void Stop();
@@ -92,7 +92,8 @@ class AudioRecorder : public media::AudioInputStream::AudioInputCallback,
   bool is_recording_;
 
   media::AudioInputStream* stream_;
-  DecodeSamplesCallback decode_callback_;
+
+  RecordedSamplesCallback decode_callback_;
 
   // ProvideInput will use this buffer as its source.
   const media::AudioBus* temp_conversion_buffer_;