This regressed in "Optimize ValidateDrawAttribs: Part 2."

Bug: chromium:834943
Bug: angleproject:1391
Change-Id: I217719d76b0524ed7900e18bcc4ca1280ec7b6ff
Reviewed-on: https://chromium-review.googlesource.com/1020280
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>