Implementing wxScreenDC::GetAsBitmap on Mac.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@53822 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/mac/carbon/dcscreen.h

@@ -23,11 +23,14 @@ class WXDLLEXPORT wxScreenDC: public wxWindowDC
   wxScreenDC();
   virtual ~wxScreenDC();
 
+  wxBitmap DoGetAsBitmap(const wxRect*) const;
+
   // Compatibility with X's requirements for
   // drawing on top of all windows
   static bool StartDrawingOnTop(wxWindow* WXUNUSED(window)) { return TRUE; }
   static bool StartDrawingOnTop(wxRect* WXUNUSED(rect) = NULL) { return TRUE; }
   static bool EndDrawingOnTop() { return TRUE; }
+
  private:
 #if wxMAC_USE_CORE_GRAPHICS
 	void* m_overlayWindow;