This prevents us from prematurely overwriting the packets in the history
if the RTT is underestimated.
Bug: webrtc:8766
Change-Id: I042e8ce74cdce2a0451596f4217779fc856b51f4
Reviewed-on: https://webrtc-review.googlesource.com/42960
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21735}