Remove old texture op factories

Change-Id: I526cd01be501bf356307f00deb2c3067ab16de8f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/223927
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
3 files changed