added DoPrepareDC()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@28331 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/scrolwin.h

@@ -127,7 +127,7 @@ public:
 
     // Override this function if you don't want to have wxScrolledWindow
     // automatically change the origin according to the scroll position.
-    virtual void PrepareDC(wxDC& dc);
+    void PrepareDC(wxDC& dc) { DoPrepareDC(); }
 
     // lay out the window and its children
     virtual bool Layout();
@@ -164,6 +164,8 @@ public:
     void ViewStart(int *x, int *y) const { GetViewStart( x, y ); }
 #endif // WXWIN_COMPATIBILITY_2_2
 
+    virtual void DoPrepareDC(wxDC& dc);
+
 protected:
     wxWindow             *m_targetWindow;
     int                   m_xScrollPixelsPerLine;