[xcb] Safety check whether we have a QApplication in mapViewport
Review Request #126397 - Created Dec. 17, 2015 and discarded
We observed that with Compiz as window manager various applications crash if they use QGuiApplication instead of QApplication. The reason for this is that on Compiz the mapViewport code paths are used and that has a widgets dependency. This change should ensure that applications do at least not crash in this condition. BUG: 354811
User in referenced bug report tested it, works.
Looks like this boils down to multiple qApp->desktop()->size() calls, ie. displayWidth/displayHeight in kwinglobals.h, right?
We could just "borrow" that code and kick the qApp dep then?