Add swarming support for MB (and the GN bots) in the chromium recipes.

scripts/slave/recipe_modules/chromium_tests/api.py

 # Copyright 2014 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.
 
 import contextlib
 import copy
 import json
 
 from infra.libs.infra_types import freeze, thaw
 from recipe_engine import recipe_api
@@ skipping 109 matching lines @@
         except self.m.step.StepFailure:
           # As part of deapplying patch we call runhooks without the patch.
           self.deapply_patch(update_step)
           raise
       else:
         self.m.chromium.runhooks()
 
     test_spec_file = bot_config.get('testing', {}).get('test_spec_file',
                                                        '%s.json' % mastername)
 
-    if self.m.chromium.c.project_generator.tool == 'mb':
-      self.m.chromium.run_mb(mastername, buildername)
-
     # TODO(phajdan.jr): Bots should have no generators instead.
     if bot_config.get('disable_tests'):
       test_spec = {}
       scripts_compile_targets = {}
     else:
       test_spec = self.read_test_spec(self.m, test_spec_file)
       test_spec_path = self.m.path['checkout'].join('testing', 'buildbot',
                                                  test_spec_file)
 
       scripts_compile_targets = \
@@ skipping 531 matching lines @@
   def get_compile_targets_for_scripts(self):
     return self.m.python(
         name='get compile targets for scripts',
         script=self.m.path['checkout'].join(
             'testing', 'scripts', 'get_compile_targets.py'),
         args=[
             '--output', self.m.json.output(),
             '--',
         ] + self.get_common_args_for_scripts(),
         step_test_data=lambda: self.m.json.test_api.output({}))