Adds AnimationContainer, which can be used to group a set of

app/app_base.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.
 
 {
   'target_defaults': {
     'variables': {
       'app_base_target': 0,
     },
     'target_conditions': [
@@ skipping 77 matching lines @@
       # the 64-bit target, but it doesn't work due to a bug in gyp
       'direct_dependent_settings': {
         'include_dirs': [
           '..',
         ],
       },
       'sources': [
         # Files that are not required for Win64 Native Client loader
         'active_window_watcher_x.cc',
         'active_window_watcher_x.h',
+        'animation_container.cc',
+        'animation_container.h',
         'animation.cc',
         'animation.h',
         'bidi_line_iterator.cc',
         'clipboard/clipboard.cc',
         'clipboard/clipboard.h',
         'clipboard/clipboard_linux.cc',
         'clipboard/clipboard_mac.mm',
         'clipboard/clipboard_util_win.cc',
         'clipboard/clipboard_util_win.h',
         'clipboard/clipboard_win.cc',
@@ skipping 158 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }