removing the menu from the public API of wxChoice on osx

on iOS pickers are having data sources that are not implemented using a menu, therefore the implementation API had to be changed

include/wx/osx/core/private.h

@@ -726,7 +726,7 @@ private:
     wxDECLARE_NO_COPY_CLASS(wxTextWidgetImpl);
 };
 
-// common interface for all implementations
+// common interface for all combobox implementations
 class WXDLLIMPEXP_CORE wxComboWidgetImpl
 
 {
@@ -753,6 +753,41 @@ public :
     virtual int FindString(const wxString& WXUNUSED(text)) const { return -1; }
 };
 
+//
+// common interface for choice
+//
+
+class WXDLLIMPEXP_CORE wxChoiceWidgetImpl
+
+{
+public :
+    wxChoiceWidgetImpl() {}
+
+    virtual ~wxChoiceWidgetImpl() {}
+
+    virtual int GetSelectedItem() const { return -1; }
+
+    virtual void SetSelectedItem(int WXUNUSED(item)) {}
+
+    virtual size_t GetNumberOfItems() const = 0;
+
+    virtual void InsertItem(size_t pos, int itemid, const wxString& text) = 0;
+
+    virtual void RemoveItem(size_t pos) = 0;
+
+    virtual void Clear()
+    {
+        size_t count = GetNumberOfItems();
+        for ( size_t i = 0 ; i < count ; i++ )
+        {
+            RemoveItem( 0 );
+        }
+    }
+
+    virtual void SetItem(int pos, const wxString& item) = 0;
+};
+
+
 //
 // common interface for buttons
 //