Split the matrix component of sksg::Transform into its own, free-floating,
chainable node.
Update the composite transform animator to target matrix nodes instead of
transform nodes.
Update the layer transform attachment logic to follow "parent" references,
and build matrix inheritance chains on the fly.
TBR=
Change-Id: I017e5e462274c2cc210730e057b3ea2e7de5c0cb
Reviewed-on: https://skia-review.googlesource.com/90803
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
18eafd922d