Also removed some older effects that weren't interesting, improved others,
cleaned up the unused functions in several, and renamed most of them to
reflect which feature they're demonstrating.
Change-Id: Ib44a00ec3d25e852a1d1661918137ba13d30c86b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/244119
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
