Qt: constify arguments

modules/gui/qt4/components/playlist/playlist_model.cpp

@@ -875,7 +875,7 @@ void PLModel::search( const QString& search_text )
 }
 
 /*********** Popup *********/
-void PLModel::popup( QModelIndex & index, QPoint &point, QModelIndexList list )
+void PLModel::popup( const QModelIndex & index, const QPoint &point, const QModelIndexList &list )
 {
     int i_id = index.isValid() ? itemId( index ) : rootItem->i_id;
 

modules/gui/qt4/components/playlist/playlist_model.hpp

@@ -87,7 +87,7 @@ public:
     int itemId( const QModelIndex &index ) const;
 
     /* Actions */
-    void popup( QModelIndex & index, QPoint &point, QModelIndexList list );
+    void popup( const QModelIndex & index, const QPoint &point, const QModelIndexList &list );
     void doDelete( QModelIndexList selected );
     void search( const QString& search_text );
     void sort( int column, Qt::SortOrder order );