The windows header must be included before versionhelpers.h.

BUG=angle:649

Change-Id: Ifee95b2918ea039f9a1c93ad0244bf2d35bd8570
Reviewed-on: https://chromium-review.googlesource.com/201462Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>