This removes the temporary defines now that Chromium is up-to-date.

Bug: angleproject:2806
Change-Id: I8e3308d6b80e49c2b2a7a698ee5d8ad40f442475
Reviewed-on: https://chromium-review.googlesource.com/1227031Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>