[skottie] Add shape layer Offset Paths support

Based on SkPathOps for now.

Change-Id: Id27c8a235cbd4ab5083735b67cf5d2635ee16cfc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/300497
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Mike Reed <reed@google.com>
7 files changed