This CL adds a parameter to the BirateProber field trial config, which
allows the prober to actually discard probe cluster is pacer scheduling
is too delayed. Today it just keeps going at a too low rate.
Some refactoring was needed anyway, so also switch to using unit types
in more places.
Initially keeps legacy behavior default, to verify no perf regressions.
Bug: webrtc:11780
Change-Id: I9edd114773b10a8d86b54a1a0398a4052aab9dd5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/179090
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31756}
b9d3809418