neteq_rtpplay: Add one more RTP header extension and fix some stats

The extension ID for transport sequence number is added to the list of
known RTP header extensions. Also, the minimum and maximum waiting
time for packets is now aggregated as minimum and maximum,
respectively, not as averages.

BUG=none

Review-Url: https://codereview.webrtc.org/3004783003
Cr-Original-Commit-Position: refs/heads/master@{#19593}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 9657172a81f6caf150b431c2b756a0a2a69f850c
1 file changed