We create the SequentialTask only if:
* We have no old computed values and we have animation name style in the new
computed values.
* Any animation properties is changed.
* display property is changed from 'none' and we have animation name style.
* display property is changed to 'none'.
In a subsequent patch we skip the SequentialTask if we have no running
animations and the display propery is changed to 'none'.