Push one function from the Mac drag/drop util code to ui/.

ui/ui.gyp

 # Copyright (c) 2011 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'target_defaults': {
     'conditions': [
@@ skipping 60 matching lines @@
         'base/clipboard/clipboard_aurax11.cc',
         'base/clipboard/clipboard_gtk.cc',
         'base/clipboard/clipboard_mac.mm',
         'base/clipboard/clipboard_util_win.cc',
         'base/clipboard/clipboard_util_win.h',
         'base/clipboard/clipboard_win.cc',
         'base/clipboard/scoped_clipboard_writer.cc',
         'base/clipboard/scoped_clipboard_writer.h',
         'base/cocoa/base_view.h',
         'base/cocoa/base_view.mm',
+        'base/dragdrop/cocoa_dnd_util.h',
+        'base/dragdrop/cocoa_dnd_util.mm',
         'base/dragdrop/drag_drop_types_gtk.cc',
         'base/dragdrop/drag_drop_types.h',
         'base/dragdrop/drag_drop_types_win.cc',
         'base/dragdrop/drag_source.cc',
         'base/dragdrop/drag_source.h',
         'base/dragdrop/drop_target.cc',
         'base/dragdrop/drop_target.h',
         'base/dragdrop/gtk_dnd_util.cc',
         'base/dragdrop/gtk_dnd_util.h',
         'base/dragdrop/os_exchange_data.cc',
@@ skipping 516 matching lines @@
                 'shutil.copyfile(\'<(ui_copy_target)\', \'<(ui_copy_dest)\'); ' \
                 'os.chmod(\'<(ui_copy_dest)\', 0700)'
               ]
             }
           ],
         },
       ],
     }],
   ],
 }