Extend chromium_tests trigger to work across masters.

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 collections
 import contextlib
 import copy
 import itertools
 import json
 
@@ skipping 412 matching lines @@
             build_url=self._build_gs_archive_url(
                 mastername, master_config, buildername),
             build_revision=build_revision,
             cros_board=self.m.chromium.c.TARGET_CROS_BOARD,
             # TODO(machenbach): Make asan a configuration switch.
             package_dsym_files=(
                 self.m.chromium.c.gyp_env.GYP_DEFINES.get('asan') and
                 self.m.chromium.c.HOST_PLATFORM == 'mac'),
         )
 
-      for loop_buildername, builder_dict in sorted(
+      trigger_specs = []
+      for loop_mastername, loop_buildername, builder_dict in sorted(
           bot_db.bot_configs_matching_parent_buildername(
               mastername, buildername)):
         trigger_spec = {
             'builder_name': loop_buildername,
             'properties': {},
         }
+        if mastername != loop_mastername:
+          trigger_spec['bucket'] = 'master.' + loop_mastername
         for name, value in update_step.presentation.properties.iteritems():
           if name.startswith('got_'):
             trigger_spec['properties']['parent_' + name] = value
-        self.m.trigger(trigger_spec)
+        trigger_specs.append(trigger_spec)
+      if trigger_specs:
+        self.m.trigger(*trigger_specs)
 
     if bot_config.get('archive_build') and not self.m.tryserver.is_tryserver:
       self.m.chromium.archive_build(
           'archive_build',
           bot_config['gs_bucket'],
           bot_config.get('gs_acl'),
           mode='dev'
       )
     if bot_config.get('cf_archive_build') and not self.m.tryserver.is_tryserver:
        self.m.archive.clusterfuzz_archive(
@@ skipping 379 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({}))