Make download items drag sources on OS X.

chrome/chrome_browser.gypi

 # Copyright (c) 2010 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': '<(library)',
       'msvs_guid': '5BF908A7-68FB-4A4B-99E3-8C749F1FE4EA',
@@ skipping 412 matching lines @@
         'browser/cocoa/constrained_window_mac.h',
         'browser/cocoa/constrained_window_mac.mm',
         'browser/cocoa/cookie_tree_node.h',
         'browser/cocoa/cookie_tree_node.mm',
         'browser/cocoa/cookies_window_controller.h',
         'browser/cocoa/cookies_window_controller.mm',
         'browser/cocoa/custom_home_pages_model.h',
         'browser/cocoa/custom_home_pages_model.mm',
         'browser/cocoa/delayedmenu_button.h',
         'browser/cocoa/delayedmenu_button.mm',
+        'browser/cocoa/download_item_button.h',
+        'browser/cocoa/download_item_button.mm',
         'browser/cocoa/download_item_cell.h',
         'browser/cocoa/download_item_cell.mm',
         'browser/cocoa/download_item_controller.h',
         'browser/cocoa/download_item_controller.mm',
         'browser/cocoa/download_item_mac.h',
         'browser/cocoa/download_item_mac.mm',
         'browser/cocoa/download_shelf_controller.h',
         'browser/cocoa/download_shelf_controller.mm',
         'browser/cocoa/download_shelf_mac.h',
         'browser/cocoa/download_shelf_mac.mm',
         'browser/cocoa/download_shelf_view.h',
         'browser/cocoa/download_shelf_view.mm',
         'browser/cocoa/download_started_animation_mac.mm',
         'browser/cocoa/download_util_mac.h',
         'browser/cocoa/download_util_mac.mm',
+        'browser/cocoa/draggable_button.h',
+        'browser/cocoa/draggable_button.mm',
         'browser/cocoa/edit_search_engine_cocoa_controller.h',
         'browser/cocoa/edit_search_engine_cocoa_controller.mm',
         'browser/cocoa/encoding_menu_controller_delegate_mac.h',
         'browser/cocoa/encoding_menu_controller_delegate_mac.mm',
         'browser/cocoa/event_utils.h',
         'browser/cocoa/event_utils.mm',
         'browser/cocoa/extension_install_prompt.mm',
         'browser/cocoa/extension_view_mac.h',
         'browser/cocoa/extension_view_mac.mm',
         'browser/cocoa/extensions/browser_action_button.h',
@@ skipping 2148 matching lines @@
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: