Implement the download arrow animation for Mac

chrome/chrome.gyp

 # Copyright (c) 2009 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,
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
     # the link of the actual chrome (or chromium) executable on
@@ skipping 767 matching lines @@
         '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/encoding_menu_controller_delegate_mac.h',
         'browser/cocoa/encoding_menu_controller_delegate_mac.mm',
         'browser/cocoa/find_bar_bridge.h',
         'browser/cocoa/find_bar_bridge.mm',
         'browser/cocoa/find_bar_cocoa_controller.h',
         'browser/cocoa/find_bar_cocoa_controller.mm',
         'browser/cocoa/find_bar_view.h',
         'browser/cocoa/find_bar_view.mm',
         'browser/cocoa/first_run_dialog.h',
         'browser/cocoa/first_run_dialog.mm',
@@ skipping 4420 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],
   ],  # 'conditions'
 }