Make Scene::windowClosed() a Q_SLOT

This commit just makes the declaration of windowClosed() in Class Scene be a Q_SLOT.
The inheriting classes SceneOpenGL and SceneXRender are updated as well.

scene.h

@@ -59,8 +59,6 @@ public:
 
     // a new window has been created
     virtual void windowAdded(Toplevel*) = 0;
-    // a window has been closed
-    virtual void windowClosed(Toplevel*, Deleted*) = 0;
     // a window has been destroyed
     virtual void windowDeleted(Deleted*) = 0;
     // Flags controlling how painting is done.
@@ -102,6 +100,8 @@ public Q_SLOTS:
     virtual void windowOpacityChanged(KWin::Toplevel* c) = 0;
     // shape/size of a window changed
     virtual void windowGeometryShapeChanged(KWin::Toplevel* c) = 0;
+    // a window has been closed
+    virtual void windowClosed(KWin::Toplevel* c, KWin::Deleted* deleted) = 0;
 protected:
     // shared implementation, starts painting the screen
     void paintScreen(int* mask, QRegion* region);

scene_opengl.cpp

@@ -220,7 +220,7 @@ void SceneOpenGL::windowAdded(Toplevel* c)
     windows[ c ]->updateShadow(c->shadow());
 }
 
-void SceneOpenGL::windowClosed(Toplevel* c, Deleted* deleted)
+void SceneOpenGL::windowClosed(KWin::Toplevel* c, KWin::Deleted* deleted)
 {
     assert(windows.contains(c));
     if (deleted != NULL) {

scene_opengl.h

@@ -52,7 +52,6 @@ public:
     }
     virtual void paint(QRegion damage, ToplevelList windows);
     virtual void windowAdded(Toplevel*);
-    virtual void windowClosed(Toplevel*, Deleted*);
     virtual void windowDeleted(Deleted*);
 
 protected:
@@ -62,6 +61,7 @@ protected:
 public Q_SLOTS:
     virtual void windowOpacityChanged(KWin::Toplevel* c);
     virtual void windowGeometryShapeChanged(KWin::Toplevel* c);
+    virtual void windowClosed(KWin::Toplevel* c, KWin::Deleted* deleted);
 private:
     bool selectMode();
     bool initTfp();

scene_xrender.cpp

@@ -307,7 +307,7 @@ void SceneXrender::windowOpacityChanged(KWin::Toplevel* c)
     w->discardAlpha();
 }
 
-void SceneXrender::windowClosed(Toplevel* c, Deleted* deleted)
+void SceneXrender::windowClosed(KWin::Toplevel* c, KWin::Deleted* deleted)
 {
     assert(windows.contains(c));
     if (deleted != NULL) {

scene_xrender.h

@@ -48,7 +48,6 @@ public:
     }
     virtual void paint(QRegion damage, ToplevelList windows);
     virtual void windowAdded(Toplevel*);
-    virtual void windowClosed(Toplevel*, Deleted*);
     virtual void windowDeleted(Deleted*);
     Picture bufferPicture();
 protected:
@@ -57,6 +56,7 @@ protected:
 public Q_SLOTS:
     virtual void windowOpacityChanged(KWin::Toplevel* c);
     virtual void windowGeometryShapeChanged(KWin::Toplevel* c);
+    virtual void windowClosed(KWin::Toplevel* c, KWin::Deleted* deleted);
 private:
     void paintTransformedScreen(int mask);
     void createBuffer();