This is a follow-up to change 232904 that also validates that the timestamp from the heartbeat ack isn't negative (which the fuzzer managed to set it to). Bug: chromium:1252515 Change-Id: Idaac570589dbdaaee67b7785f6232b60226e88e1 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/234582 Reviewed-by: Florent Castelli <orphis@webrtc.org> Commit-Queue: Victor Boivie <boivie@webrtc.org> Cr-Commit-Position: refs/heads/main@{#35168}