Add makeBuffer and caps to GrOnFlushResourceProvider

Bug: skia:
Change-Id: Ie3101ca20743a953621815bdae886c995d39c9e6
Reviewed-on: https://skia-review.googlesource.com/20315
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2 files changed