TimedItem.parentGroup should be an AnimationGroup, not a TimedItem
TimedItem.parentGroup should be an AnimationGroup, not a TimedItem

TimedItem attempts to use the following methods and properties of its
parentGroup member.
- iterationTime
- paused
- _childrenStateModified()
- type
- remove()
- indexOf()
- _addChild()

Of these, only the first two are provided by TimedItem. The others are added
only by AnimationGroup.

beni55/web-animations-js-legacy,web-animations/web-animations-js-legacy,beni55/web-animations-js-legacy,web-animations/web-animations-js-legacy,birtles/web-animations-js,beni55/web-animations-js-legacy,dstockwell/web-animations-js,birtles/web-animations-js,dstockwell/web-animations-js,beni55/web-animations-js-legacy,birtles/web-animations-js,web-animations/web-animations-js-legacy