Add a placeholder stat for logging the estimated residual echo likelihood.

webrtc/media/engine/webrtcvoiceengine.cc

Index: webrtc/media/engine/webrtcvoiceengine.cc
diff --git a/webrtc/media/engine/webrtcvoiceengine.cc b/webrtc/media/engine/webrtcvoiceengine.cc
index 9636ff32fc4fc98a21402e6d11c4d1433da6ed10..29a4f556fac858c14a4118edb7d89071e9f225fa 100644
--- a/webrtc/media/engine/webrtcvoiceengine.cc
+++ b/webrtc/media/engine/webrtcvoiceengine.cc
@@ -2567,6 +2567,7 @@ bool WebRtcVoiceMediaChannel::GetStats(VoiceMediaInfo* info) {
     sinfo.echo_delay_std_ms = stats.echo_delay_std_ms;
     sinfo.echo_return_loss = stats.echo_return_loss;
     sinfo.echo_return_loss_enhancement = stats.echo_return_loss_enhancement;
+    sinfo.residual_echo_likelihood = stats.residual_echo_likelihood;
     sinfo.typing_noise_detected = (send_ ? stats.typing_noise_detected : false);
     info->senders.push_back(sinfo);
   }