Summary:
The Scale effect and the Glide effect have to animate only ordinary
windows(i.e. the ones that are considered to be apps).

On X11, in order to distinguish ordinary windows from combo box popups,
popup menus, and other popups, those effects check whether given window
is managed.

On Wayland, there is no concept of managed/unmanaged windows.

XDG Shell protocol defines 2 surface roles:
* xdg_toplevel;
* and, xdg_popup.

The former can be used to implement typical windows, the ones that can
be minimized, maximized, etc.

The latter can be used to implement tooltips, popup menus, etc. Thus,
that's a good criteria to filter popup windows.

CCBUG: 398100

Reviewers: #kwin, graesslin, davidedmundson

Reviewed By: #kwin, graesslin, davidedmundson

Subscribers: davidedmundson, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D15117