Include animations and transitions in the cascade
Instead of applying animations and transitions to styled elements,
include them in the cascade. This allows them to interact properly with
things like font-size and !important rules.
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Instead of applying animations and transitions to styled elements,
include them in the cascade. This allows them to interact properly with
things like font-size and !important rules.
This begins to address #26625 by properly applying CSS variables during
keyframe computation and no longer using `apply_declarations`. Instead,
walk the declarations, combining them into IntermediateComputedKeyframe,
maintaining declarations that modify CSS custom properties. Then compute
a set of AnimationValues for each keyframe and use those to produce
interpolated animation values.
For legacy reasons, transitions were marked as finished after updating the
style. According to the spec, they should be marked as finished when
animations are updated and before restyle. This change does that as well
as preventing replacement of finished transitions.
Having finished transitions survive a full restyle cycle and allowing
the replacement of finished transition, could lead to issues were
removed from the global list of animating transitions too soon:
1. A transitions finishes
2. Restyle
3. Transitions is marked as finished and events are queued
4. Restyle cancels finished transition and replaces it instead of
clearing finished transition
5. Events are sent for the incorrectly canceled transition removing it
completely from the list of running transitions due to the extra
event.
