Adds an example effect that spawns particles along an SkPath.
Change-Id: I53f3c02fefec814bd9e16f3ac593eac4cf6a297c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/341418
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
