This saves us some startup time in the D3D11 Renderer.

BUG=angleproject:1014

Change-Id: I5d2607b58a86ee0a8932032a0f8a31b21d39b525
Reviewed-on: https://chromium-review.googlesource.com/275774Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>