This is without Metal specific shader translator implemented yet.

Bug: angleproject:2634
Change-Id: I95d589442251c9ba111bd05a2dc379a36739046c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1855069Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>