AE layers can be tagged for auto-orient - i.e. they observe an
additional rotation component dependent on the position property
animation (position derivative/tangent).
Augment Vec2KeyframeAnimator to optionally track orientation, for both
temporal/linear and spatial (motion-path) keyframes. Update
TransformAdapter2D to use this orientation when attached to layer
transforms.
Change-Id: I616e45a07b088e9e566b4f88450e95f9315b727c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291716
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
