Add wxTopLevelWindow::SetRepresentedFilename().

This currently is only implemented under OS X and sets the proxy icon there
but could be implemented to do something useful under the other platforms too
in the future.

Closes #13797.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70295 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/toplevel.h

@@ -503,6 +503,20 @@ public:
     */
     virtual bool OSXIsModified() const;
 
+    /**
+        Sets the file name represented by this wxTopLevelWindow.
+
+        Under OS X, this file name is used to set the "proxy icon", which
+        appears in the window title bar near its title, corresponding to this
+        file name. Under other platforms it currently doesn't do anything but
+        it is harmless to call it now and it might be implemented to do
+        something useful in the future so you're encouraged to use it for any
+        window representing a file-based document.
+
+        @since 2.9.4
+    */
+    virtual void SetRepresentedFilename(const wxString& filename);
+
     /**
         Depending on the value of @a show parameter the window is either shown
         full screen or restored to its normal state. @a style is a bit list