// Some presentation controllers (e.g. UIImagePickerController) require portrait orientation and will throw exception if it is not supported.
// At the same time enabling all orientations by returning UIInterfaceOrientationMaskAll might cause unwanted orientation change
// (e.g. when using UIActivityViewController to "share to" another application, iOS will use supportedInterfaceOrientations to possibly reorient).
// So to avoid exception we are returning combination of constraints for root view controller and orientation requested by iOS.
// _forceInterfaceOrientationMask is updated in willChangeStatusBarOrientation, which is called if some presentation controller insists on orientation change.