BUG=angleproject:2270
TEST=dEQP-GLES31.functional.compute.indirect_dispatch.*

Change-Id: Id062a80188b2a37f28833aaae8e6d31bac382276
Reviewed-on: https://chromium-review.googlesource.com/802763
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>