Stop passing --build-tool=ninja in master configs

scripts/master/factory/dart/dart_factory.py

 #!/usr/bin/python
 # Copyright 2013 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.
 
 """Utility class to generate a Dart-specific BuildFactory.
 
 Based on gclient_factory.py.
 """
 
@@ skipping 314 matching lines @@
     if trigger_schedulers:
       dart_cmd_obj.AddTrigger(trigger.Trigger(
           schedulerNames=trigger_schedulers,
           waitForFinish=False,
           updateSourceStamp=False))
 
     return factory
 
 
 class DartUtils(object):
-  mac_options = ['--compiler=goma-clang',

[Nico, 2016/06/23 16:58:28]

goma-clang and goma mean the same thing these days, so changing this too while
i'm here

-                 '--build-tool=ninja',
-                 'dartium_builder']
-  linux_options = ['--compiler=goma', '--build-tool=ninja', 'dartium_builder']
-  win_options = ['--build-tool=ninja', 'dartium_builder']
+  mac_options = ['--compiler=goma', 'dartium_builder']
+  linux_options = ['--compiler=goma', 'dartium_builder']
+  win_options = ['dartium_builder']
 
 
   win_rel_factory_properties = {
     'gclient_env': {
       'GYP_DEFINES': 'fastbuild=1',
     },
     'gclient_transitive': True,
     'no_gclient_branch': True,
     'gclient_timeout': 3600,
     'annotated_script': 'dart_buildbot_run.py',
@@ skipping 379 matching lines @@
                          builders=notifying_builders))
       else:
         statuses.append(
             MailNotifier(fromaddr=self._active_master.from_address,
                          mode='problem',
                          sendToInterestedUsers=send_to_interested_useres,
                          extraRecipients=extra_recipients,
                          lookup=master_utils.UsersAreEmails(),
                          builders=notifying_builders))
     return statuses