Made AudioReceiveStream a mixer participant.

webrtc/audio/audio_receive_stream.cc

Index: webrtc/audio/audio_receive_stream.cc
diff --git a/webrtc/audio/audio_receive_stream.cc b/webrtc/audio/audio_receive_stream.cc
index 57e62f50fd05984a60acaa188325904eea03a8ad..9721c73e81f02817b68acb2682e8b0f547092163 100644
--- a/webrtc/audio/audio_receive_stream.cc
+++ b/webrtc/audio/audio_receive_stream.cc
@@ -271,6 +271,11 @@ bool AudioReceiveStream::DeliverRtp(const uint8_t* packet,
   return channel_proxy_->ReceivedRTPPacket(packet, length, packet_time);
 }
 
+MixerAudioSource::AudioFrameWithMuted
+AudioReceiveStream::GetAudioFrameWithMuted(int32_t id, int sample_rate_hz) {
+  return channel_proxy_->GetAudioFrameWithMuted(id, sample_rate_hz);
+}
+
 VoiceEngine* AudioReceiveStream::voice_engine() const {
   internal::AudioState* audio_state =
       static_cast<internal::AudioState*>(audio_state_.get());