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

masters/master.tryserver.chromium/master.cfg

Index: masters/master.tryserver.chromium/master.cfg
===================================================================
--- masters/master.tryserver.chromium/master.cfg	(revision 228622)
+++ masters/master.tryserver.chromium/master.cfg	(working copy)
@@ -175,20 +175,13 @@
   factory_properties = (factory_properties or {}).copy()
   run_default_swarm_tests = run_default_swarm_tests or []
 
-  # Make app_list_unittests an opt-in target for initial verification on non-
-  # ChromeOS platforms. TODO(tapted): Remove this when verified.
-  if platform in ('win32', 'win64', 'mac'):
-    platform_optional_tests = ['app_list_unittests']
-  else:
-    platform_optional_tests = []
-
   factory_properties.setdefault('non_default', [
       'check_licenses',
       'chromedriver_tests',
       'courgette_unittests',
       'sync_integration_tests',
       'url_unittests',
-    ] + platform_optional_tests)
+    ])
 
   factory_properties.setdefault('gclient_env', {})
   factory_properties['gclient_env'].setdefault('GYP_DEFINES', '')
@@ -403,6 +396,7 @@
     slavebuilddir='linux_aura')
 
 linux_aura_tests = [
+  'app_list_unittests_br',
   'aura_br',
   'base_unittests_br',
   'browser_tests_br',
@@ -432,6 +426,7 @@
 ]
 
 linux_aura_options = [
+  'app_list_unittests',
   'aura_builder',
   'base_unittests',
   'browser_tests',