Drop unwanted dependencies on chromium_tests recipe module

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 12 matching lines @@
 
 Revision Y will be the revision property as provided by buildbot or HEAD (i.e.
 in a forced build with no revision provided).
 """
 
 from recipe_engine.types import freeze
 
 DEPS = [
   'depot_tools/bot_update',
   'chromium',
+  'chromium_checkout',
   'chromium_tests',
   'depot_tools/gclient',
   'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/platform',
   'recipe_engine/properties',
   'recipe_engine/python',
   'recipe_engine/raw_io',
   'recipe_engine/step',
   'test_utils',
@@ skipping 82 matching lines @@
 
   # Sync component to current component revision.
   component_revision = api.properties.get('revision') or 'HEAD'
   api.gclient.c.revisions[bot_config['component']['path']] = (
       bot_config['component']['revision'] % component_revision)
 
   # Ensure we remember the chromium revision.
   api.gclient.c.got_revision_mapping['src'] = 'got_cr_revision'
 
   context = {}
-  checkout_dir = api.chromium_tests.get_checkout_dir(bot_config)
+  checkout_dir = api.chromium_checkout.get_checkout_dir(bot_config)
   if checkout_dir:
     context['cwd'] = checkout_dir
 
   # Run all steps in the checkout dir (consistent with chromium_tests).
   with api.step.context(context):
     # TODO(phajdan.jr): remove redundant **context below once we fix things
     # to behave the same without it.
     step_result = api.bot_update.ensure_checkout(force=True, **context)
 
     api.chromium.ensure_goma()
@@ skipping 121 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))
   )