Refactor finding of instance times

Make FindInstanceTime(...) only handle the "strictly greater than" case
and rename it to NextAfter(...), adjusting the implementation
accordingly. This can be used for all the callers of
FindInstanceTime(...) except ResolveInterval(...).
Fold FindInstanceTime(...) with the "greater or equal" case into
ResolveInterval(...).

Bug: 1029573
Change-Id: Id727514e10586576796ecfacc5a045114217050c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1944473
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720892}
2 files changed