Create SkVMCallbacks, to bundle the child-sampling routines
I'm about to add more callbacks, and the collection of std::function was
getting unmaintainable. This mirrors the pipeline-stage generator, and
also is structured to share more code among the different runtime effect
objects.
Change-Id: Ib82042781051471a6743401db45ce24540bfa253
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/481684
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed
