Add stats for frequency offset when converting RTP timestamp to NTP time.

webrtc/video/rtp_streams_synchronizer.cc

Index: webrtc/video/rtp_streams_synchronizer.cc
diff --git a/webrtc/video/rtp_streams_synchronizer.cc b/webrtc/video/rtp_streams_synchronizer.cc
index 885dad39797fcebeb585e4d3fe4c564d8b3a33e6..b23487d4704a3911e79e5d30d4737204bbaa477c 100644
--- a/webrtc/video/rtp_streams_synchronizer.cc
+++ b/webrtc/video/rtp_streams_synchronizer.cc
@@ -168,7 +168,9 @@ void RtpStreamsSynchronizer::Process() {
 }
 
 bool RtpStreamsSynchronizer::GetStreamSyncOffsetInMs(
-    const VideoFrame& frame, int64_t* stream_offset_ms) const {
+    const VideoFrame& frame,
+    int64_t* stream_offset_ms,
+    double* estimated_freq_khz) const {
   rtc::CritScope lock(&crit_);
   if (voe_channel_id_ == -1)
     return false;
@@ -186,8 +188,8 @@ bool RtpStreamsSynchronizer::GetStreamSyncOffsetInMs(
   }
 
   int64_t latest_video_ntp;
-  if (!RtpToNtpMs(frame.timestamp(), video_measurement_.rtcp,
-                  &latest_video_ntp)) {
+  if (!RtpToNtpMsAndReturnFreq(frame.timestamp(), video_measurement_.rtcp,
+                               &latest_video_ntp, estimated_freq_khz)) {
     return false;
   }