Add check_licenses step to the buildbot.

masters/master.tryserver.chromium/master.cfg

 # -*- python -*-
 # ex: set syntax=python:
 # Copyright (c) 2011 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.
 
 # READ THIS:
 # See http://dev.chromium.org/developers/testing/chromium-build-infrastructure
 
 # These modules come from scripts, which must be in the PYTHONPATH.
@@ skipping 147 matching lines @@
   'net_unittests',
   'sql_unittests',
   'ui_tests',
   'unit_tests',
   # dbus_unittests is not sharded because it takes less than 1 second to run.
   'dbus_unittests']
 
 # Linux builder
 linux_tests = [
   'check_deps',
+  'check_licenses',
   'base',
   'net',
   'googleurl',
   'unit',
   'ui',
   'browser_tests',
   'test_shell',
   'webkit_unit',
   'media',
   'printing',
@@ skipping 772 matching lines @@
 ####### PROJECT IDENTITY
 
 # The 'projectURL' string will be used to provide a link
 # from buildbot HTML pages to your project's home page.
 c['projectURL'] = 'http://dev.chromium.org/developers/testing/try-server-usage'
 
 # Buildbot master url:
 c['buildbotURL'] = 'http://build.chromium.org/p/tryserver.chromium/'
 
 # vi: set ts=4 sts=2 sw=2 et: