Workspace::updateClientLayer operates on AbstractClient

Requires a virtual updateLayer in AbstractClient. Default implementation
does nothing.

abstract_client.cpp

@@ -137,4 +137,8 @@ void AbstractClient::doSetActive()
 {
 }
 
+void AbstractClient::updateLayer()
+{
+}
+
 }

abstract_client.h

@@ -193,6 +193,7 @@ public:
      * @param mode The tile mode (left/right) to give this window.
      */
     virtual void setQuickTileMode(QuickTileMode mode, bool keyboard = false) = 0;
+    virtual void updateLayer();
 
     // TODO: remove boolean trap
     static bool belongToSameApplication(const AbstractClient* c1, const AbstractClient* c2, bool active_hack = false);

client.h

@@ -392,7 +392,7 @@ public:
     virtual Layer layer() const;
     Layer belongsToLayer() const;
     void invalidateLayer();
-    void updateLayer();
+    void updateLayer() override;
     int sessionStackingOrder() const;
 
     void setModal(bool modal);

layers.cpp

@@ -102,7 +102,7 @@ namespace KWin
 // Workspace
 //*******************************
 
-void Workspace::updateClientLayer(Client* c)
+void Workspace::updateClientLayer(AbstractClient* c)
 {
     if (c)
         c->updateLayer();

workspace.h

@@ -180,7 +180,7 @@ public:
     void lowerClientRequest(Client* c, NET::RequestSource src, xcb_timestamp_t timestamp);
     void restackClientUnderActive(AbstractClient*);
     void restack(AbstractClient *c, AbstractClient *under, bool force = false);
-    void updateClientLayer(Client* c);
+    void updateClientLayer(AbstractClient* c);
     void raiseOrLowerClient(AbstractClient*);
     void resetUpdateToolWindowsTimer();
     void restoreSessionStackingOrder(Client* c);