This should give us a bound on how much we can improve startup
time in ANGLE on D3D11 across all users.

BUG=angleproject:944
BUG=436191

Change-Id: Ie9047c0424429aecec5f6d7be8e119ebcc53fbe3
Reviewed-on: https://chromium-review.googlesource.com/266524Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>