Use std::extent rather than arraysize in the VR API.

This is purely a mechanical change; there is no intended behavior change.

BUG=837308
R=vollick@chromium.org

Change-Id: I557797032e6b94217fe580a421524ae469f1b506
Reviewed-on: https://chromium-review.googlesource.com/c/1399455
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620745}
4 files changed