Stop media stream source when audio capture error occurs.

content/renderer/media/media_stream_audio_source.h

Index: content/renderer/media/media_stream_audio_source.h
diff --git a/content/renderer/media/media_stream_audio_source.h b/content/renderer/media/media_stream_audio_source.h
index 235227189090955df93ef26a83f749be91ed1bc3..485f1a1278683df52dd0d50275ef6e672652f06f 100644
--- a/content/renderer/media/media_stream_audio_source.h
+++ b/content/renderer/media/media_stream_audio_source.h
@@ -17,6 +17,10 @@
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace content {
 
 class MediaStreamAudioTrack;
@@ -123,6 +127,9 @@ class CONTENT_EXPORT MediaStreamAudioSource
   void DeliverDataToTracks(const media::AudioBus& audio_bus,
                            base::TimeTicks reference_time);
 
+  // Called by subclasses when capture error occurs.

[miu, 2016/10/19 22:43:22]

Please add:

 // Note: This can be called on any thread, and will post a task to the main
thread to stop the source soon.

[xjz, 2016/10/19 23:59:36]

Done.

+  void OnAudioCaptureError(const std::string& why);

[miu, 2016/10/19 22:43:22]

naming nit (says what it does more accurately): StopSourceOnError()

[xjz, 2016/10/19 23:59:36]

Done.

+
  private:
   // MediaStreamSource override.
   void DoStopSource() final;
@@ -146,6 +153,8 @@ class CONTENT_EXPORT MediaStreamAudioSource
   // Manages tracks connected to this source and the audio format and data flow.
   MediaStreamAudioDeliverer<MediaStreamAudioTrack> deliverer_;
 
+  const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;

[miu, 2016/10/19 22:43:22]

Please add comment (mostly the same as the one for the |thread_checker_|):

  // Task Runner for main thread. Also used to check that all methods that could
cause object graph or data flow changes are being called on the main thread.

[xjz, 2016/10/19 23:59:36]

Done.

+
   // Provides weak pointers so that MediaStreamAudioTracks won't call
   // StopAudioDeliveryTo() if this instance dies first.
   base::WeakPtrFactory<MediaStreamAudioSource> weak_factory_;