Add app_list_unittests as a test step and tree closer on mac, win, and linux_aura.

masters/master.chromium.linux/master_gatekeeper_cfg.py

 # 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.
 
 from master import gatekeeper
 from master import master_utils
 
 # This is the list of the builder categories and the corresponding critical
 # steps. If one critical step fails, gatekeeper will close the tree
 # automatically.
 # Note: don't include 'update scripts' since we can't do much about it when
 # it's failing and the tree is still technically fine.
 categories_steps = {
   '': ['update', 'runhooks'],
   'testers': [
+    'app_list_unittets',
     'aura_unittests',
     'base_unittests',
     'browser_tests',
     'cacheinvalidation_unittests',
     'cc_unittests',
     'chrome_frame_net_tests',
     'chromedriver2_unittests',
     'components_unittests',
     'compositor_unittests',
     'content_browsertests',
@@ skipping 81 matching lines @@
       relayhost=config.Master.smtp,
       subject='buildbot %(result)s in %(projectName)s on %(builder)s, '
               'revision %(revision)s',
       extraRecipients=[],
       lookup=master_utils.FilterDomain(),
       forgiving_steps=forgiving_steps,
       tree_status_url=None,
       sheriffs=['sheriff_android'],
       public_html='../master.chromium/public_html',
       use_getname=True))