Can dump SkPicture to an skp, but only for debugging purposes
(no deserialization).
Bug: skia:
Change-Id: I37f3c4dcfdd70b665748773ee6b5135329c6240a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206262
Reviewed-by: Florin Malita <fmalita@chromium.org>
