Add findOrMakeStaticBuffer method to GrResourceProvider

Bug: skia:
Change-Id: Ie47f00bf8542462d719df0d08972794861ec4a2b
Reviewed-on: https://skia-review.googlesource.com/86283
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
9 files changed