Call RAF callbacks with monotonic timestamp

Bug: 833902
Change-Id: Iaec0c5d4bff2d9988edc11a3f6c8958a9f34ba63
Reviewed-on: https://chromium-review.googlesource.com/1035904


Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Justin Novosad <junov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555086}