CSS Animations and Web Animations are built on InterpolationTypes.
The AnimatableValue code path used by CSS Transitions is largely a duplication of the same logic.
CSS Transitions should be rewritten on top of InterpolationTypes instead of AnimatableValues. Doing this would help enable transitions on custom properties and reduce redundant interpolation logic in the code base.
Comment 1 by suzyh@chromium.org
, Jan 17 2017