Remove shim GrBackendDrawableInfo.h

Client CLs:
 - https://crrev.com/c/5302435
 - http://ag/26946195

Change-Id: I682cd8f62837a093c839af3fca8e00059efa052a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/839997
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
2 files changed