recipe engine: extract infra-specific paths out of the engine

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 recipe_engine import recipe_api
@@ skipping 131 matching lines @@
   OK_ATTRS = ('pardir', 'sep', 'pathsep')
 
   # Because the native 'path' type in python is a str, we filter the *args
   # of these methods to stringify them first (otherwise they would be getting
   # recipe_util_types.Path instances).
   FILTER_METHODS = ('abspath', 'basename', 'dirname', 'exists', 'join', 'split',
                     'splitext')
 
   def get_config_defaults(self):
     return {
-      'PLATFORM': self.m.platform.name,
       'CURRENT_WORKING_DIR': self._startup_cwd,
       'TEMP_DIR': self._temp_dir,
     }
 
   def __init__(self, **kwargs):
     super(PathApi, self).__init__(**kwargs)
     config_types.Path.set_tostring_fn(
       PathToString(self, self._test_data))
 
     # Used in mkdtemp when generating and checking expectations.
@@ skipping 10 matching lines @@
       self._startup_cwd = ['/', 'FakeTestingCWD']
       # Appended to placeholder '[TMP]' to get fake path in test.
       self._temp_dir = ['/']
 
     self._config_set = False
 
   def _lazy_set_config(self):
     if self._config_set:
       return
     self._config_set = True
-
-    path_config = self.m.properties.get('path_config')
-    if path_config in ('kitchen', 'swarming'):
-      self.set_config(path_config)
-    else:
-      self.set_config('buildbot')
+    self.set_config('BASE')
 
   def mock_add_paths(self, path):
     """For testing purposes, assert that |path| exists."""
     if self._test_data.enabled:
       self._path_mod.mock_add_paths(path)
 
   def assert_absolute(self, path):
     assert self.abspath(path) == str(path), '%s is not absolute' % path
 
   def mkdtemp(self, prefix):
@@ skipping 44 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)