GitLab

Previously the requestAnimatioNFrame timestamp would start from a
very large possibly negative number when the date was overidden.

Change-Id: I5faf417a035488ea651c35fc2bc8f45c3b8ba7d4
Reviewed-on: https://chromium-review.googlesource.com/972985Reviewed-by: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548380}