Fixed the racing in the resampler of webrtc when two streams are calling OnData()

content/renderer/media/webrtc_audio_device_impl.h

Index: content/renderer/media/webrtc_audio_device_impl.h
diff --git a/content/renderer/media/webrtc_audio_device_impl.h b/content/renderer/media/webrtc_audio_device_impl.h
index f515c6e24cbc2bcea6d2bcb7fb027e6cc39b23e0..89f145991cc155aefdf58bbc3b695eeb9eb5d71b 100644
--- a/content/renderer/media/webrtc_audio_device_impl.h
+++ b/content/renderer/media/webrtc_audio_device_impl.h
@@ -385,6 +385,10 @@ class CONTENT_EXPORT WebRtcAudioDeviceImpl
   // |recording_| and |microphone_volume_|.
   mutable base::Lock lock_;
 
+  // Used to protect the racing of calling OnData() since there can be more
+  // than one input streams calling OnData().

[henrika (OOO until Aug 14), 2014/01/09 10:07:14]

Do we know on which threads these calls are made? If so, should we document it?

[no longer working on chromium, 2014/01/09 10:18:32]

Threads can be the from WebRtcAudioCapturer and from WebAudio, or from different
WebAudio threads.

I am not sure if can define which threads they are since it is up to the JS.

+  mutable base::Lock capture_callback_lock_;
+
   bool initialized_;
   bool playing_;
   bool recording_;