moved wxOverlay into overlay.* files and out of dc.h/dcbase.cpp; implemented wxOverlay for wxDirectFB port

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42340 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dfb/dcclient.h

@@ -26,14 +26,21 @@ public:
     wxWindowDC(wxWindow *win);
     virtual ~wxWindowDC();
 
+    virtual wxWindow *GetWindow() const { return m_win; }
+
 protected:
     // initializes the DC for painting on given window; if rect!=NULL, then
     // for painting only on the given region of the window
     void InitForWin(wxWindow *win, const wxRect *rect);
 
 private:
+    wxWindow *m_win;
+    wxRect    m_winRect; // rectangle of the window being painted
+
     bool m_shouldFlip; // flip the surface when done?
 
+    friend class wxOverlayImpl; // for m_shouldFlip;
+
     DECLARE_DYNAMIC_CLASS(wxWindowDC)
     DECLARE_NO_COPY_CLASS(wxWindowDC)
 };