delay adding Unmanaged clients by 50ms

This provides some sort of synthetic XSYNC support
for unmanaged clients and allows them to do an initial
update after mapping and before being painted (prevent
flicker)
Also it helps with Unmanaged clients performing quick
map/unmap/map cycles what also seems to induce the black
window issue on the nvidia blob.

CCBUG: 284888
BUG: 319184
FIXED-IN: 4.11
REVIEW: 111292

effects.cpp

@@ -555,9 +555,9 @@ void EffectsHandlerImpl::slotClientAdded(Client *c)
 }
 
 void EffectsHandlerImpl::slotUnmanagedAdded(Unmanaged *u)
-{   // regardless, unmanaged windows are -yet?- not synced anyway
-    setupUnmanagedConnections(u);
-    emit windowAdded(u->effectWindow());
+{
+    // it's never initially ready but has synthetic 50ms delay
+    connect(u, SIGNAL(windowShown(KWin::Toplevel*)), SLOT(slotUnmanagedShown(KWin::Toplevel*)));
 }
 
 void EffectsHandlerImpl::slotClientShown(KWin::Toplevel *t)
@@ -569,6 +569,14 @@ void EffectsHandlerImpl::slotClientShown(KWin::Toplevel *t)
         emit windowAdded(c->effectWindow());
 }
 
+void EffectsHandlerImpl::slotUnmanagedShown(KWin::Toplevel *t)
+{   // regardless, unmanaged windows are -yet?- not synced anyway
+    Q_ASSERT(dynamic_cast<Unmanaged*>(t));
+    Unmanaged *u = static_cast<Unmanaged*>(t);
+    setupUnmanagedConnections(u);
+    emit windowAdded(u->effectWindow());
+}
+
 void EffectsHandlerImpl::slotDeletedRemoved(KWin::Deleted *d)
 {
     emit windowDeleted(d->effectWindow());

effects.h

@@ -217,6 +217,7 @@ protected Q_SLOTS:
     void slotClientAdded(KWin::Client *c);
     void slotClientShown(KWin::Toplevel*);
     void slotUnmanagedAdded(KWin::Unmanaged *u);
+    void slotUnmanagedShown(KWin::Toplevel*);
     void slotWindowClosed(KWin::Toplevel *c);
     void slotClientActivated(KWin::Client *c);
     void slotDeletedRemoved(KWin::Deleted *d);

toplevel.h

@@ -342,6 +342,7 @@ protected Q_SLOTS:
     void checkScreen();
     void setupCheckScreenConnection();
     void removeCheckScreenConnection();
+    void setReadyForPainting();
 
 protected:
     virtual ~Toplevel();
@@ -353,7 +354,6 @@ protected:
     void addDamageFull();
     void getWmClientLeader();
     void getWmClientMachine();
-    void setReadyForPainting();
     /**
      * @returns Whether there is a compositor and it is active.
      **/

unmanaged.cpp

@@ -25,6 +25,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "deleted.h"
 #include "xcbutils.h"
 
+#include <QTimer>
 #include <QDebug>
 
 #include <X11/extensions/shape.h>
@@ -35,7 +36,9 @@ namespace KWin
 Unmanaged::Unmanaged()
     : Toplevel()
 {
+    ready_for_painting = false;
     connect(this, SIGNAL(geometryShapeChanged(KWin::Toplevel*,QRect)), SIGNAL(geometryChanged()));
+    QTimer::singleShot(50, this, SLOT(setReadyForPainting()));
 }
 
 Unmanaged::~Unmanaged()