We can't rely on the previous screen and current screen to accurately
reflect whether or not the window has been moved from one screen to
another, or if the window just stayed on the same screen but the screen
was reconfigured by macOS. The reasons for this are many-fold, but
include factors such as Qt using the screen of the top level window
to resolve the screen of the child windows, and AppKit delivering
screen change events in an order that makes things harder to track.
The result is that we need to always send screen change events, for
all windows, including child windows, and we also need to restart the
display link by re-requesting an update request if needed, so that
child windows that are running animations will continue to animate
on the new screen.
Change-Id: I0b87849c41323e92c08f5115842be067fa8f8490
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
19d13f8b2d