Move recipe engine to third_party/recipe_engine.

scripts/slave/recipe_modules/path/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 functools
 import os
 import sys
 import tempfile
 
-from slave import recipe_api
-from slave import recipe_config_types
+from recipe_engine import recipe_api
+from recipe_engine import recipe_config_types
 
 
 def PathToString(api, test):
   def PathToString_inner(path):
     assert isinstance(path, recipe_config_types.Path)
     base_path = None
     suffix = path.platform_ext.get(api.m.platform.name, '')
     if isinstance(path.base, recipe_config_types.NamedBasePath):
       name = path.base.name
       if name in api.c.dynamic_paths:
@@ skipping 206 matching lines @@
     if name in self.OK_ATTRS:
       return getattr(self._path_mod, name)
     if name in self.FILTER_METHODS:
       return string_filter(getattr(self._path_mod, name))
     raise AttributeError("'%s' object has no attribute '%s'" %
                          (self._path_mod, name))  # pragma: no cover
 
   def __dir__(self):  # pragma: no cover
     # Used for helping out show_me_the_modules.py
     return self.__dict__.keys() + list(self.OK_ATTRS + self.FILTER_METHODS)