This will simplify the code somewhat. It should no longer be
necessary now that we have the nVidia workaround.

BUG=angle:705

Change-Id: I1abe1abd9f03472341ce4315975a76c56b252bb4
Reviewed-on: https://chromium-review.googlesource.com/216111Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>