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

content/renderer/media/webrtc_audio_device_impl.h

 // Copyright 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_WEBRTC_AUDIO_DEVICE_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_WEBRTC_AUDIO_DEVICE_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 367 matching lines @@
   // Cached value of the current audio delay on the input/capture side.
   int input_delay_ms_;
 
   // Cached value of the current audio delay on the output/renderer side.
   int output_delay_ms_;
 
   // Protects |recording_|, |output_delay_ms_|, |input_delay_ms_|, |renderer_|
   // |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_;
 
   // Used for histograms of total recording and playout times.
   base::Time start_capture_time_;
   base::Time start_render_time_;
 
   // Stores latest microphone volume received in a CaptureData() callback.
   // Range is [0, 255].
   uint32_t microphone_volume_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRtcAudioDeviceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBRTC_AUDIO_DEVICE_IMPL_H_