Bring back the file dialogs for chrome AURA.

ui/shell_dialogs/linux_ui_shell_dialog.h

Index: ui/shell_dialogs/linux_ui_shell_dialog.h
===================================================================
--- ui/shell_dialogs/linux_ui_shell_dialog.h	(revision 0)
+++ ui/shell_dialogs/linux_ui_shell_dialog.h	(revision 0)
@@ -0,0 +1,31 @@
+// 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_LINUX_UI_SHELL_DIALOG_H_
+#define UI_SHELL_DIALOGS_LINUX_UI_SHELL_DIALOG_H_
+
+#include "ui/base/linux_ui.h"
+#include "ui/shell_dialogs/shell_dialogs_export.h"
+
+#if defined(USE_AURA) && !defined(USE_ASH) && defined(OS_LINUX)
+namespace ui {
+// This subclass of the base LinuxUI class provides a way for subclasses to
+// override the CreateSelectFileDialog function declared here to return
+// native file dialogs.
+class SHELL_DIALOGS_EXPORT LinuxUIShellDialog : public ui::LinuxUI {
+ public:
+  virtual ~LinuxUIShellDialog() {}
+
+  // Returns a native file selection dialog.
+  virtual SelectFileDialog* CreateSelectFileDialog(
+      SelectFileDialog::Listener* listener,
+      SelectFilePolicy* policy) const = 0;
+};
+
+}  // namespace ui
+#endif
+
+
+#endif  // UI_SHELL_DIALOGS_LINUX_UI_SHELL_DIALOG_H_
+