[Graphite] Support caching of buffers.

Bug: skia:12754
Change-Id: I8b74fadabee2ec90c20f9b53ff4946a3e2062cd3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/515956
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
2 files changed