Extract functions from path recipe module so that step can depend on it

scripts/slave/recipes/boringssl.py

 # Copyright 2015 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 = [
   'bot_update',
+  'file',
   'gclient',
   'path',
   'platform',
   'properties',
   'python',
   'step',
   'test_utils',
 ]
 
 
@@ skipping 81 matching lines @@
 def GenSteps(api):
   # Sync and pull in everything.
   api.gclient.set_config('boringssl')
   api.bot_update.ensure_checkout(force=True)
   api.gclient.runhooks()
 
   # Set up paths.
   bot_utils = api.path['checkout'].join('util', 'bot')
   go_env = bot_utils.join('go', 'env.py')
   build_dir = api.path['checkout'].join('build')
-  api.path.makedirs('mkdir', build_dir)
+  api.file.makedirs('mkdir', build_dir)
 
   # If building with MSVC, all commands must run with an environment wrapper.
   # This is necessary both to find the toolchain and the runtime dlls. Rather
   # than copy the runtime to every directory where a binary is installed, just
   # run the tests with the toolchain prefix as well.
   msvc_prefix = _GetTargetMSVCPrefix(api.properties['buildername'], bot_utils)
 
   # Build BoringSSL itself.
   cmake = bot_utils.join('cmake-' + _GetHostToolSuffix(api.platform), 'bin',
                          'cmake' + _GetHostExeSuffix(api.platform))
@@ skipping 39 matching lines @@
     yield (
       api.test(buildername) +
       host_platform +
       api.properties.generic(mastername='client.boringssl',
                              buildername=buildername, slavename='slavename') +
       api.override_step_data('unit tests',
                              api.test_utils.canned_test_output(True)) +
       api.override_step_data('ssl tests',
                              api.test_utils.canned_test_output(True))
     )