Use the AudioProcessing float interface in MediaStreamAudioProcessor.

media/base/audio_bus.h

Index: media/base/audio_bus.h
diff --git a/media/base/audio_bus.h b/media/base/audio_bus.h
index c78486e5e00aa5f00ce567275f0025681778ec21..d24794497f00fb832eb363700c14899896e8586b 100644
--- a/media/base/audio_bus.h
+++ b/media/base/audio_bus.h
@@ -92,6 +92,10 @@ class MEDIA_EXPORT AudioBus {
   const float* channel(int channel) const { return channel_data_[channel]; }
   void SetChannelData(int channel, float* data);
 
+  // Returns an array of pointers to each channel.
+  float** channel_data() { return &channel_data_[0]; }

[DaleCurtis, 2014/08/07 20:05:06]

This isn't okay since the pointers could be rewritten using this interface. 
Only the const* interface is allowed, callers must use SetChannelData() for
other cases.

I also don't think you should add this to AudioBus for a single user, instead
you should probably handle this with a wrapper inside the WebRTC class.

[ajm, 2014/08/08 02:20:11]

Ah true, I should have returned float* const* which is all I needed (though now
removed entirely).
Good point. If you like, you can have a look at MediaStreamAudioBus to see if
that's what you were thinking.

+  const float* const* channel_data() const { return &channel_data_[0]; }
+
   int channels() const { return static_cast<int>(channel_data_.size()); }
   int frames() const { return frames_; }
   void set_frames(int frames);