get a timestamp. Also, use -1 to signify an unset timestamp. This is what other callers do: https://source.chromium.org/chromium/chromium/src/+/main:third_party/webrtc/modules/audio_coding/acm2/audio_coding_module.cc;l=306;drc=bbe4aed2302dc763935496b80a5cefb6a42d912d No-Try because of lack of infra lack of capacity on macs. No-Try: True Bug: webrtc:11327 Change-Id: Ide0c0633579b6b2be3eea9912b13f858760de0ad Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219781 Commit-Queue: Paul Hallak <phallak@google.com> Reviewed-by: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34074}