Update the build rule for media router tests (e2e) and the mapping.

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 149 matching lines @@
   'cronet_test',
 
   # These are listed in Builders that are skipped for other reasons.
   'chrome_junit_tests',
   'components_invalidation_impl_junit_tests',
   'components_policy_junit_tests',
   'components_web_restrictions_junit_tests',
   'content_junit_tests',
   'content_junit_tests',
   'junit_unit_tests',
+  'media_router_tests',
   'net_junit_tests',
   'net_junit_tests',
   'ui_junit_tests',
   'webapk_client_junit_tests',
   'webapk_shell_apk_junit_tests',
 
   # These tests are only run on WebRTC CI.
   'AppRTCMobileTest',
   'android_junit_tests',
   'audio_decoder_unittests',
@@ skipping 296 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())