Make all the rest of the recipes explicitly specify GIT_MODE

scripts/slave/recipes/blink_downstream.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.
 
 """
 This recipe can be used by components like v8 to verify blink tests with a
 low false positive rate. Similar to a trybot, this recipe compares test
 failures from a build with a current component revision with test failures
 from a build with a pinned component revision.
 
@@ skipping 96 matching lines @@
         caller_api.test_utils._summarize_retried_test(caller_api, t)
 
 
 def RunSteps(api):
   mastername = api.properties.get('mastername')
   buildername = api.properties.get('buildername')
   master_dict = BUILDERS.get(mastername, {})
   bot_config = master_dict.get('builders', {}).get(buildername)
 
   # Sync chromium to HEAD.
-  api.gclient.set_config('chromium')
+  api.gclient.set_config('chromium', GIT_MODE=True)
   api.gclient.c.revisions['src'] = 'HEAD'
   api.chromium.set_config('blink',
                           **bot_config.get('chromium_config_kwargs', {}))
 
   for c in bot_config.get('gclient_apply_config', []):
     api.gclient.apply_config(c)
   for c in bot_config.get('chromium_apply_config', []):
     api.chromium.apply_config(c)
 
   # Sync component to current component revision.
@@ skipping 140 matching lines @@
   # and compare the lists of failing tests).
   yield (
     api.test('too_many_failures_for_retcode') +
     properties('client.v8.fyi', 'V8-Blink Linux 64') +
     api.override_step_data(with_patch,
                            canned_test(passing=False,
                                        num_additional_failures=125)) +
     api.override_step_data(without_patch,
                            canned_test(passing=True, minimal=True))
   )