Move recipe engine to third_party/recipe_engine.

scripts/slave/recipe_modules/chromium/api.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.
 
 import re
 
-from slave import recipe_api
-from slave import recipe_util
+from recipe_engine import recipe_api
+from recipe_engine import recipe_util
 
 from . import builders
 from . import steps
 
 class TestLauncherFilterFileInputPlaceholder(recipe_util.Placeholder):
   def __init__(self, api, tests):
     self.raw = api.m.raw_io.input('\n'.join(tests))
     super(TestLauncherFilterFileInputPlaceholder, self).__init__()
 
   def render(self, test):
@@ skipping 744 matching lines @@
             '--output', self.m.json.output(),
             '--',
         ] + self.get_common_args_for_scripts(),
         step_test_data=lambda: self.m.json.test_api.output({}))
 
   def download_lto_plugin(self):
     return self.m.python(
         name='download LTO plugin',
         script=self.m.path['checkout'].join(
             'build', 'download_gold_plugin.py'))