Add web-animations-js to polymer WATCHLISTS entry

WATCHLISTS

 # 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.
 
 # Watchlist Rules
 # Refer: http://dev.chromium.org/developers/contributing-code/watchlists
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.
 
@@ skipping 844 matching lines @@
     },
     'plugin': {
       'filepath': 'chrome/browser/plugin|chrome/plugin/|'\
         'chrome/common/plugin',
     },
     'policy_definitions': {
       'filepath': 'components/policy/resources/policy_templates.json',
     },
     'polymer': {
       'filepath': 'third_party/polymer/|'\
+                  'third_party/web-animations-js/|'\
                   'tools/polymer|'\
                   'ui/webui/resources/polymer_resources.grdp',
     },
     'precache': {
       'filepath': '[pP]recache'
     },
     'prepopulated_engines': {
       'filepath': 'components/search_engines/prepopulated_engines.json',
     },
     'prerender': {
@@ skipping 1291 matching lines @@
                          'raymes+watch@chromium.org'],
     'windows_sandboxing': ['pennymac+watch@chromium.org',
                            'wfh+watch@chromium.org'],
     'x11': ['derat+watch@chromium.org',
             'sadrul@chromium.org',
             'yusukes+watch@chromium.org'],
     'xml': ['dominicc+watchlist@chromium.org'],
     'zoom': ['wjmaclean@chromium.org'],
   },
 }