Start consolidating cross-port file selection code into ui/base/dialogs.

ui/ui.gyp

 # Copyright (c) 2012 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,
   },
   'includes': [
     'ui_resources.gypi',
@@ skipping 91 matching lines @@
         'base/cocoa/underlay_opengl_hosting_window.h',
         'base/cocoa/underlay_opengl_hosting_window.mm',
         'base/cocoa/window_size_constants.h',
         'base/cocoa/window_size_constants.mm',
         'base/cursor/cursor.cc',
         'base/cursor/cursor.h',
         'base/cursor/cursor_win.cc',
         'base/cursor/cursor_x11.cc',
         'base/dialogs/base_shell_dialog.cc',
         'base/dialogs/base_shell_dialog.h',
+        'base/dialogs/select_file_policy.cc',
+        'base/dialogs/select_file_policy.h',
         'base/dialogs/selected_file_info.cc',
         'base/dialogs/selected_file_info.h',
         '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',
@@ skipping 619 matching lines @@
                 'shutil.copyfile(\'<(ui_copy_target)\', \'<(ui_copy_dest)\'); ' \
                 'os.chmod(\'<(ui_copy_dest)\', 0700)'
               ]
             }
           ],
         },
       ],
     }],
   ],
 }