This will save us some queries on D3D11 startup.

BUG=angleproject:1014

Change-Id: I5aaeec43d3b9bc73d011de17e2abac902ac3b7b9
Reviewed-on: https://chromium-review.googlesource.com/275776Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>