[skottie] Add a property setter sample/GM

skottie_colorize: press 'c' to cycle through stroke/fill colors.
Change-Id: I7fa9dcd67822df37e97cafabe088c4b9ded9c622
TBR=
Reviewed-on: https://skia-review.googlesource.com/156882
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
2 files changed