ui: Add out-of-line copy ctors for complex classes.

ui/shell_dialogs/select_file_dialog_mac.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_MAC_H_
 #define UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include <map>
@@ skipping 45 matching lines @@
                       gfx::NativeWindow owning_window,
                       void* params) override;
 
  private:
   friend class test::SelectFileDialogMacTest;
 
   // Struct to store data associated with a file dialog while it is showing.
   struct DialogData {
     DialogData(void* params_,
                base::scoped_nsobject<ExtensionDropdownHandler> handler);
+    DialogData(const DialogData& other);
 
     // |params| user data associated with this file dialog.
     void* params;
 
     // Extension dropdown handler corresponding to this file dialog.
     base::scoped_nsobject<ExtensionDropdownHandler> extension_dropdown_handler;
 
     ~DialogData();
   };
 
@@ skipping 20 matching lines @@
 
   bool hasMultipleFileTypeChoices_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectFileDialogImpl);
 };
 
 }  // namespace ui
 
 #endif  //  UI_SHELL_DIALOGS_SELECT_FILE_DIALOG_MAC_H_