Update MediaRecorderHandler to use AudioTrackRecorder

content/renderer/media/mock_media_stream_registry.h

 // Copyright (c) 2013 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_MOCK_MEDIA_STREAM_REGISTRY_H_
 #define CONTENT_RENDERER_MEDIA_MOCK_MEDIA_STREAM_REGISTRY_H_
 
 #include <string>
 
 #include "content/renderer/media/media_stream_registry_interface.h"
 
 namespace content {
 
 // This class encapsulates creation of a Blink MediaStream having inside the
 // necessary Blink and Chromium, track and source. The Chrome Video source is
 // a mock.
 class MockMediaStreamRegistry final : public MediaStreamRegistryInterface {
  public:
   MockMediaStreamRegistry();
 
   void Init(const std::string& stream_url);
   void AddVideoTrack(const std::string& track_id);
+  void AddAudioTrack(const std::string& track_id);
   blink::WebMediaStream GetMediaStream(const std::string& url) override;
 
   const blink::WebMediaStream test_stream() const { return test_stream_; }
 
   void reset() {
     test_stream_.reset();
   }
 
  private:
   blink::WebMediaStream test_stream_;
   std::string stream_url_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MOCK_MEDIA_STREAM_REGISTRY_H_