Added a new echo likelihood stat that reports the maximum value from a previous time period.

webrtc/audio/audio_send_stream.cc

Index: webrtc/audio/audio_send_stream.cc
diff --git a/webrtc/audio/audio_send_stream.cc b/webrtc/audio/audio_send_stream.cc
index aff605fe6a6845b995fd2082d458d8e5b9f45f4c..3831b8d27a1997c008dee230bf056bce74922776 100644
--- a/webrtc/audio/audio_send_stream.cc
+++ b/webrtc/audio/audio_send_stream.cc
@@ -210,6 +210,8 @@ webrtc::AudioSendStream::Stats AudioSendStream::GetStats() const {
       audio_processing_stats.echo_return_loss_enhancement.instant();
   stats.residual_echo_likelihood =
       audio_processing_stats.residual_echo_likelihood;
+  stats.residual_echo_likelihood_recent_max =
+      audio_processing_stats.residual_echo_likelihood_recent_max;
 
   internal::AudioState* audio_state =
       static_cast<internal::AudioState*>(audio_state_.get());