Move recipe engine to third_party/recipe_engine.

scripts/slave/recipe_modules/properties/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.
 
 from infra.libs.infra_types import freeze, thaw
-from slave import recipe_api
+from recipe_engine import recipe_api
 import collections
 
 # Use RecipeApiPlain because collections.Mapping has its own metaclass.
 # Additionally, nothing in this class is a composite_step (nothing in this class
 # is any sort of step :).
 class PropertiesApi(recipe_api.RecipeApiPlain, collections.Mapping):
   """
   Provide an immutable mapping view into the 'properties' for the current run.
 
   The value of this api is equivalent to this transformation of the legacy
@@ skipping 22 matching lines @@
     # changes.
     blacklist = set([
       'buildbotURL',
     ])
     return {k: v for k, v in self.iteritems() if k not in blacklist}
 
   def thaw(self):
     """Returns a vanilla python jsonish dictionary of properties."""
 
     return thaw(self._engine.properties)