Fixes#2840
Related to #2842
This builds on #2842 by missing a key situation: when native fullscreen
is toggled using the menu bar items it doesn't go through our
`FullscreenStyle` machinery so we don't trigger fullscreen change
events.
This commit makes it so that our FullscreenStyle always listens for
native fullscreen change (even in non-native modes) to fire a fullscreen
did change event. This way we can always rely on the event to be fired
when fullscreen changes no matter what.
Fixes#2370
Comparing NSScreens directly was fragile. It appears that AppKit/Cocoa
can return different instances of NSScreen for the same screen for
unknown reasons between calls to windowDidChangeScreen. I don't fully
understand why this happens.
In any case, our comparison was not safe. Instad, we now keep track of
of the CGDirectDisplayID for each screen and compare those instead.
