QMenuBar: Get rid of QMenuBarPrivate::nativeMenuBar

Instead of trying to keep that variable in sync with platformMenuBar
state, just check whether platformMenuBar exists instead.

Now QMenuBar::isNativeMenuBar() is more reliable, and will not return
true if the QPA plugin provides no platform menu bar.

Also, remove useless restrictions for code using isNativeMenuBar().
That method is available on all platforms for a long time, not only on
macOS or WinCE.

This makes sure local menus do not appear if global menus are available,
and setVisible(true) is called.

Change-Id: I7a5944c64376b4714a38ad981089df8a151c3403
Task-number: QTBUG-54793
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

0 files changed, 0 insertions, 0 deletions