Add default ctors and Create() to wxDirDialog and wxFileDialog in wxOSX.

Allow two-step creation of these classes.

Closes #15316.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74476 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/dirdlg.h

@@ -19,7 +19,22 @@
 class WXDLLIMPEXP_CORE wxDirDialog : public wxDirDialogBase
 {
 public:
+    wxDirDialog() { Init(); }
+
     wxDirDialog(wxWindow *parent,
+                const wxString& message = wxDirSelectorPromptStr,
+                const wxString& defaultPath = wxT(""),
+                long style = wxDD_DEFAULT_STYLE,
+                const wxPoint& pos = wxDefaultPosition,
+                const wxSize& size = wxDefaultSize,
+                const wxString& name = wxDirDialogNameStr)
+    {
+        Init();
+
+        Create(parent,message,defaultPath,style,pos,size,name);
+    }
+
+    void Create(wxWindow *parent,
                 const wxString& message = wxDirSelectorPromptStr,
                 const wxString& defaultPath = wxT(""),
                 long style = wxDD_DEFAULT_STYLE,
@@ -47,6 +62,9 @@ private:
     WX_NSObject m_sheetDelegate;
 #endif
 
+    // Common part of all ctors.
+    void Init();
+
     DECLARE_DYNAMIC_CLASS(wxDirDialog)
 };