Qt objects are treated as identities so remove the copy constructor and
an assignment operator. See, http://doc.qt.io/qt-5/object.html#identity-vs-value
IIRC some Qt objects(like QImage) have copy constructor for implicit data sharing,
but VirtualOutput doesn't have anything to share.
Also, it [this patch] fixes a compiler warning:
/home/vlad/KDE/src/kde/workspace/kwin/plugins/platforms/virtual/virtual_output.cpp: In copy constructor ‘KWin::VirtualOutput::VirtualOutput(const KWin::VirtualOutput&)’: /home/vlad/KDE/src/kde/workspace/kwin/plugins/platforms/virtual/virtual_output.cpp:30:1: warning: base class ‘class QObject’ should be explicitly initialized in the copy constructor [-Wextra] VirtualOutput::VirtualOutput(const VirtualOutput &o) ^~~~~~~~~~~~~