QWaylandLayerShellIntegration has virtual hooks for Xdg Activation.
This is important to hook up in layer shell because activation using
requestActivate in Qt will go through this path. It also means we have
support for us to drop the implementation in KWindowSystem in favour of
calling into Qt.
With QWaylandWindow::setShellIntegration(), it's possible to use
xdg-shell and layer-shell protocols in the same process. It's important
for plasmashell, where we want to use the layer shell protocol for
special surfaces such as the desktop background, and the xdg shell
protocol for dialogs.
In order to make a QWindow use the layer shell protocol, you need to
call LayerShellQt::Window::get() before the window is mapped.
