This will have the contract of having a successful API call once we
call into the ANGLE internals, having successfully passed valiation.

BUG=angle:571

Change-Id: Ia8d6eccc1e42bdf9e9cc5c10094a08729b42778a
Reviewed-on: https://chromium-review.googlesource.com/200075Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>