Add force=True to all chromium recipes.

scripts/slave/recipes/chromium.py

 # 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.
 
 DEPS = [
   'adb',
   'amp',
   'bisect_tester',
   'depot_tools/bot_update',
   'chromium',
@@ skipping 35 matching lines @@
   mastername = api.properties.get('mastername')
   buildername = api.properties.get('buildername')
 
   if mastername == 'tryserver.chromium.perf' and api.chromium_tests.builders[
       mastername]['builders'][buildername]['bot_type'] == 'tester':
     api.bisect_tester.upload_job_url()
 
   bot_config = api.chromium_tests.create_bot_config_object(
       mastername, buildername)
   api.chromium_tests.configure_build(bot_config)
-  update_step, bot_db = api.chromium_tests.prepare_checkout(bot_config)
+  update_step, bot_db = api.chromium_tests.prepare_checkout(
+      bot_config, force=True)
   tests, tests_including_triggered = api.chromium_tests.get_tests(
       bot_config, bot_db)
   compile_targets = api.chromium_tests.get_compile_targets(
       bot_config, bot_db, tests_including_triggered)
   api.chromium_tests.compile_specific_targets(
       bot_config, update_step, bot_db,
       compile_targets, tests_including_triggered)
   api.chromium_tests.archive_build(
       mastername, buildername, update_step, bot_db)
   api.chromium_tests.download_and_unzip_build(mastername, buildername,
@@ skipping 934 matching lines @@
     api.test('amp_split_recipe_collect_failure') +
     api.properties(
         mastername='chromium.fyi',
         buildername='Android Tests (amp split)',
         slavename='build1-a1',
         buildnumber='77457',
         parent_build_archive_url='gs://test-domain/test-archive.zip'
     ) +
     api.override_step_data('[collect] base_unittests', retcode=1)
   )