ui: Cleanup class/struct forward declarations

ui/shell_dialogs/select_file_dialog.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_H_
 #define UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/shell_dialogs/base_shell_dialog.h"
 #include "ui/shell_dialogs/shell_dialogs_export.h"
 
 namespace ui {
 class SelectFileDialogFactory;
 class SelectFilePolicy;
 struct SelectedFileInfo;
-class ShellDialogsDelegate;
 
 // Shows a dialog box for selecting a file or a folder.
 class SHELL_DIALOGS_EXPORT SelectFileDialog
     : public base::RefCountedThreadSafe<SelectFileDialog>,
       public BaseShellDialog {
  public:
   enum Type {
     SELECT_NONE,
 
     // For opening a folder.
@@ skipping 175 matching lines @@
   std::unique_ptr<SelectFilePolicy> select_file_policy_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectFileDialog);
 };
 
 SelectFileDialog* CreateSelectFileDialog(SelectFileDialog::Listener* listener,
                                          SelectFilePolicy* policy);
 }  // namespace ui
 
 #endif  // UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_H_