This patch fixes two issues:
- Animation events that should go to the target element now do
(some were previously being dispatched on the animation itself.)
- We update the "previous phase" and "previous iteration" fields of
animation effects, so that we can actually detect phase changes.
This means we stop thinking animations always just started,
something that caused each animation to send 60 animationstart
events every second (to the wrong target!)
As the parser was trying to directly unwrap an unresolved duration.
Currently we are outputting the wrong results for the serialized
duration, but this is still a step forwards.
Fixes a crash seen on: https://evaparish.com/blog/how-i-edit
Previously, we were accessing the performance through the current
window object. Thus caused a crash when `animate()` was called on an
element within a document with no associated window object. The global
object is now used to access the performance object in places where
a window object is not guaranteed to exist.
