Following design decision, we want to animate AllView and FrequentView
when opening and closing with a swarm spring form.
This involves a few changes needed to allow that, since from some time
now, we are animating page changes in viewSelector, using only a fade
transition. However now we want to let appDisplay and iconGrid apply its
own animation.
For that we special case the change to and from apps page on
viewSelector to let appDisplay to animate its own items, using and API
on appDisplay which at the same time uses an API on iconGrid.
Thanks Florian Müllner for the debugging work
https://bugzilla.gnome.org/show_bug.cgi?id=734726
f160dda187