Experimentally isolate GetOpenFileName in a utility process.

ui/shell_dialogs/select_file_dialog_win.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_WIN_H_
 #define UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_WIN_H_
 
+#include <Windows.h>
+#include <commdlg.h>
+
+#include "base/callback_forward.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
 #include "ui/shell_dialogs/shell_dialogs_export.h"
 
 namespace ui {
 class SelectFilePolicy;
 
 // Implementation detail exported for unit tests.
 SHELL_DIALOGS_EXPORT std::wstring AppendExtensionIfNeeded(
     const std::wstring& filename,
     const std::wstring& filter_selected,
     const std::wstring& suggested_ext);
 
-// Intentionally not exported. Implementation detail of SelectFileDialog. Use
-// SelectFileDialog::Create() instead.
-SelectFileDialog* CreateWinSelectFileDialog(
+SHELL_DIALOGS_EXPORT SelectFileDialog* CreateWinSelectFileDialog(
+    SelectFileDialog::Listener* listener,
+    SelectFilePolicy* policy,
+    const base::Callback<bool(OPENFILENAME* ofn)>& get_open_file_name_impl);
+
+SelectFileDialog* CreateDefaultWinSelectFileDialog(
     SelectFileDialog::Listener* listener,
     SelectFilePolicy* policy);
 
 }  // namespace ui
 
 #endif  //  UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_WIN_H_