Remove legacy GrDirectContext::MakeGL

Client CLs:
 - https://github.com/flutter/engine/pull/46308
 - https://crrev.com/c/4895306
 - http://ag/24871653
 - http://ag/24876327
 - http://cl/568854625
 - http://cl/568855014
 - http://cl/568864102
 - http://cl/568885035
 - http://cl/568889136
 - http://cl/568941763
 - http://cl/569079228
 - http://cl/569475107

Change-Id: I6ed1e1f0a0a1a1dfdc6bd793189824456473a92a
Bug: b/293490566
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/764970
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
2 files changed