Add wxListCtrlBase common base class for port-specific wxListCtrl.

This base class is currently trivial, more methods will be moved to it from
the derived classes later.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70280 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/listbase.h

@@ -371,6 +371,20 @@ private:
     DECLARE_DYNAMIC_CLASS(wxListItem)
 };
 
+// ----------------------------------------------------------------------------
+// wxListCtrlBase: the base class for the main control itself.
+// ----------------------------------------------------------------------------
+
+// Unlike other base classes, this class doesn't currently define the API of
+// the real control class but is just used for implementation convenience. We
+// should define the public class functions as pure virtual here in the future
+// however.
+class WXDLLIMPEXP_CORE wxListCtrlBase : public wxControl
+{
+public:
+    wxListCtrlBase() { }
+};
+
 // ----------------------------------------------------------------------------
 // wxListEvent - the event class for the wxListCtrl notifications
 // ----------------------------------------------------------------------------