remove dead code from old factories, enum

Change-Id: I12d46c2c60539689949a08636c3a654d2298285a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/207868
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>