Drm backend: delete DrmOutput* after DrmScreens notified its users
It delays DrmOutput* deletion after screensQueried signal has triggered its logic.
Test:
Plug-in and out HDMI connected screen
Before: Crash when plugin-in
Thread 1 "kwin_wayland" received signal SIGSEGV, Segmentation fault.
KWaylandServer::OutputInterface::clientResources (this=this@entry=0x5632781af250, client=0x56327925ed40)
at /home/meven/kde/src/kwayland-server/src/server/output_interface.cpp:512
512 for (auto it = d->resources.constBegin(), end = d->resources.constEnd(); it != end; ++it) {
(gdb) bt
#0 0x00007ff6d1a5107d in KWaylandServer::OutputInterface::clientResources(KWaylandServer::ClientConnection*) const (this=this@entry=0x5632781af250, client=0x56327925ed40)
at /home/meven/kde/src/kwayland-server/src/server/output_interface.cpp:512
#1 0x00007ff6d1a7f8ec in KWaylandServer::SurfaceInterface::setOutputs(QVector<KWaylandServer::OutputInterface*> const&) (this=0x56327917ffb0, outputs=...)
at /home/meven/kde/src/kwayland-server/src/server/surface_interface.cpp:850
#2 0x00007ff6d2ef7010 in KWin::XdgShellClient::updateClientOutputs() (this=0x563278f51960)
at /home/meven/kde/src/kwin/xdgshellclient.cpp:1950
#3 0x00007ff6d02a40d7 in () at /home/meven/kde/qt5/lib/libQt5Core.so.5
#4 0x00007ff6d2f2c647 in KWin::Toplevel::frameGeometryChanged(KWin::Toplevel*, QRect const&) (this=this@entry=0x563278f51960, _t1=<optimized out>, _t1@entry=0x563278f51960, _t2=...)
at /home/meven/kde/build/kwin/kwin_autogen/EWIEGA46WW/moc_toplevel.cpp:877
#5 0x00007ff6d2eefd97 in KWin::XdgShellClient::doSetGeometry(QRect const&) (this=this@entry=0x563278f51960, rect=...) at /home/meven/kde/src/kwin/xdgshellclient.cpp:552
#6 0x00007ff6d2ef6394 in KWin::XdgShellClient::updatePendingGeometry() (this=this@entry=0x563278f51960)
at /home/meven/kde/src/kwin/xdgshellclient.cpp:1114
#7 0x00007ff6d2ef660a in KWin::XdgShellClient::handleCommitted() (this=0x563278f51960)
at /home/meven/kde/src/kwin/xdgshellclient.cpp:1306
#8 0x00007ff6d02a40d7 in () at /home/meven/kde/qt5/lib/libQt5Core.so.5
#9 0x00007ff6c2857dae in ffi_call_unix64 () at ../src/x86/unix64.S:76
#10 0x00007ff6c285771f in ffi_call (cif=<optimized out>, fn=<optimized out>, rvalue=<optimized out>, avalue=<optimized out>) at ../src/x86/ffi64.c:525After: No crash