I agree that the spec definition of this function isn't super clear
about that, but from "Web Animations 1 - 4.5. Animations"[1]:
An animation is a timing node that binds an animation effect child,
called its associated effect, to a timeline parent so that it runs. Both
of these associations are optional and configurable such that an
animation can have no associated effect or timeline at a given moment.
[1]: https://drafts.csswg.org/web-animations-1/#animations
This fixes a bug in `pause()` that canceled the pause task instead
of the play task. This issue prevented the animation from being paused
while a play task is scheduled.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
The main motivation behind this is to remove JS specifics of the Realm
from the implementation of the Heap.
As a side effect of this change, this is a bit nicer to read than the
previous approach, and in my opinion, also makes it a little more clear
that this method is specific to a JavaScript Realm.
