Make the generic SkRuntimeEffect::Make factories private

All clients have been moved to the stage-specific factories. The old
flexible factories are still used internally (for now), but this
prevents any new usage from creeping in accidentally.

Bug: skia:11813
Change-Id: I6c34dfd19b396541f9a0e2f9eab8a51591ed8b70
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/402156
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed