Move recipe engine to third_party/recipe_engine.

scripts/slave/recipe_modules/commit_position/api.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.
 
 import re
 
-from slave import recipe_api
+from recipe_engine import recipe_api
 
 
 class CommitPositionApi(recipe_api.RecipeApi):
   """Recipe module providing commit position parsing and manipulation."""
   RE_COMMIT_POSITION = re.compile('(?P<branch>.+)@{#(?P<revision>\d+)}')
   COMMIT_POS_STR = 'Cr-Commit-Position: refs/heads/master@{#%d}'
 
   @classmethod
   def parse(cls, value):
     match = cls.RE_COMMIT_POSITION.match(value)
@@ skipping 52 matching lines @@
                              stdout=self.m.raw_io.output(),
                              name='resolving hash ' + sha)
     try:
       result = int(self.parse_revision(str(step_result.stdout)))
     except ValueError:
       raise self.m.step.StepFailure(
           'Could not parse commit position from git output: ' +
           (step_result.stdout or ''))
     return result