[graphite] Impl. public image API in Image_Base via copies

Bug: b/333909822
Change-Id: I9f35225fe3eff3cae4d0e181a1ebf271805ac16a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/838256
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
7 files changed