Add new prerequisite type for GL_ENUM integers This check is not applied in this commit. Bug: angleproject:7420 Change-Id: Ie84600c21aa4829c8d8c798643719c3084597af4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3759423 Commit-Queue: Eddie Hatfield <eddiehatfield@google.com> Reviewed-by: Ian Elliott <ianelliott@google.com> Reviewed-by: Cody Northrop <cnorthrop@google.com>