use GTK+ API for setting icons instead of direct X11 calls

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@28856 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk1/toplevel.h

@@ -80,9 +80,6 @@ public:
     // from both DoSetSize() and DoSetClientSize()
     virtual void DoMoveWindow(int x, int y, int width, int height);
 
-    // set the icon for this window
-    void DoSetIcon( const wxIcon& icon );
-
     // GTK callbacks
     virtual void GtkOnSize( int x, int y, int width, int height );
     virtual void OnInternalIdle();