adapting to new inheritance of wxMemoryDC (under MSW only at the moment)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43110 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/graphicc.cpp

@@ -1166,6 +1166,10 @@ public :
 
     virtual wxGraphicsContext * CreateContext( const wxWindowDC& dc);
 
+#ifdef __WXMSW__
+    virtual wxGraphicsContext * CreateContext( const wxMemoryDC& dc);
+#endif
+
     virtual wxGraphicsContext * CreateContextFromNativeContext( void * context );
 
     virtual wxGraphicsContext * CreateContextFromNativeWindow( void * window );
@@ -1224,6 +1228,13 @@ wxGraphicsContext * wxCairoRenderer::CreateContext( const wxWindowDC& dc)
     return new wxCairoContext(this,dc);
 }
 
+#ifdef __WXMSW__
+wxGraphicsContext * wxCairoRenderer::CreateContext( const wxMemoryDC& dc)
+{
+    return NULL;
+}
+#endif
+
 wxGraphicsContext * wxCairoRenderer::CreateContextFromNativeContext( void * context )
 {
     return new wxCairoContext(this,(cairo_t*)context);