This saves us from querying a lot of the formats on startup.

BUG=angleproject:1014

Change-Id: I499625b9a131cf10791d1580d7a7b477a161045a
Reviewed-on: https://chromium-review.googlesource.com/275773Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>