Add "findOrMakeStaticBuffer" to GrOnFlushResourceProvider

Bug: skia:
Change-Id: If381c91f40566e6630799ea9985c48e2b738596e
Reviewed-on: https://skia-review.googlesource.com/23420
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2 files changed