Smooth BWE and pass it to Audio Network Adaptor.

webrtc/voice_engine/channel.h

Index: webrtc/voice_engine/channel.h
diff --git a/webrtc/voice_engine/channel.h b/webrtc/voice_engine/channel.h
index 31c44efccd12cf4038a755e9f096042d26e6cacc..84f9691ef2fbeabea0920e5c97e5d1066d7e79c8 100644
--- a/webrtc/voice_engine/channel.h
+++ b/webrtc/voice_engine/channel.h
@@ -17,6 +17,7 @@
 #include "webrtc/api/call/audio_sink.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/optional.h"
+#include "webrtc/common_audio/smoothing_filter.h"
 #include "webrtc/common_audio/resampler/include/push_resampler.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/acm2/codec_manager.h"
@@ -543,6 +544,8 @@ class Channel
 
   // TODO(ossu): Remove once GetAudioDecoderFactory() is no longer needed.
   rtc::scoped_refptr<AudioDecoderFactory> decoder_factory_;
+
+  SmoothingFilterImpl bitrate_smoother_;
 };
 
 }  // namespace voe