Run the webkit layout tests under swarming on linux_chromium_rel_ng.

testing/buildbot/manage.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """Toolbox to manage all the json files in this directory.
 
 It can reformat them in their canonical format or ensures they are well
 formatted.
 """
@@ skipping 183 matching lines @@
   'system_wrappers_unittests',
   'test_support_unittests',
   'tools_unittests',
   'video_engine_tests',
   'voice_engine_unittests',
   'webrtc_nonparallel_tests',
   'xmllite_xmpp_unittests',
 
   # isolate is currently too slow for this target.
   # http://crbug.com/524758
-  'webkit_layout_tests',
+  'webkit_layout_tests_exparchive',
 }
 
 
 class Error(Exception):
   """Processing error."""
 
 
 def get_isolates():
   """Returns the list of all isolate files."""
 
@@ skipping 264 matching lines @@
     elif args.mode == 'remaining':
       print_remaining(args.test_name, tests_location)
     return result
   except Error as e:
     sys.stderr.write('%s\n' % e)
     return 1
 
 
 if __name__ == "__main__":
   sys.exit(main())