QCocoaWindow now gets resize events from QNSViev
and does not require a NSWindow. QWindow instances
can now be inserted in NSView hierarchies. This is
useful for Qt-as-a-plugin use cases and is needed to
implement QMacNativeWidget for Qt 5.
Change-Id: Ia95ea9c22a15a3e62d1e6543466cff07390c70a2
Reviewed-by: Morten Johan Sørvig <morten.sorvig@nokia.com>