add virtual DoGetTextExtent() to allow calling the overloaded wxWindowBase::GetTextExtent() on wxWindow objects without any ugly casts/scope resolution operators

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60984 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/x11/window.cpp

@@ -1076,10 +1076,11 @@ int wxWindowX11::GetCharWidth() const
 #endif
 }
 
-void wxWindowX11::GetTextExtent(const wxString& string,
-                                int *x, int *y,
-                                int *descent, int *externalLeading,
-                                const wxFont *theFont) const
+void wxWindowX11::DoGetTextExtent(const wxString& string,
+                                  int *x, int *y,
+                                  int *descent,
+                                  int *externalLeading,
+                                  const wxFont *theFont) const
 {
     wxFont fontToUse = GetFont();
     if (theFont) fontToUse = *theFont;