sk_sp-ify GrResourceProvider some more

I believe this addresses the concerns of this particular bug (although more remains to be done)

Bug: skia:5327
Change-Id: Ie82f08f87b3cf3d7986fe4eeb16a5d2553173913
Reviewed-on: https://skia-review.googlesource.com/18599
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
22 files changed