Use base::size rather than arraysize in ppapi/.

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

BUG=837308
TBR=raymes@chromium.org

Change-Id: I72d85808c431221bac3e8f392f4be78c1856c401
Reviewed-on: https://chromium-review.googlesource.com/c/1390418
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#618841}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: ef8bbedcad363d2ec5d9c681114a0ebadff5f4f7
2 files changed