build: use class path bases, not strings

scripts/slave/recipe_modules/syzygy/config.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 types
 
-from recipe_engine.config import config_item_context, ConfigGroup, Single
+from recipe_engine.config import (
+    config_item_context, ConfigGroup, Single, Static)
 from recipe_engine.config_types import Path
 from . import api as syzygy_api
 
 
-def BaseConfig(**dummy_kwargs):
+def BaseConfig(CHECKOUT_PATH, **dummy_kwargs):
   return ConfigGroup(
+    CHECKOUT_PATH = Static(CHECKOUT_PATH),
+
     official_build = Single(bool, empty_val=False, required=False),
     unittests_gypi = Single(Path, required=False),
     version_file = Single(Path, required=False),
   )
 
 
 config_ctx = config_item_context(BaseConfig)
 
 
 @config_ctx(is_root=True)
 def BASE(c):
   pass
 
 
 @config_ctx()
 def syzygy(c):
   c.official_build = False
-  c.unittests_gypi = Path('[CHECKOUT]', 'syzygy', 'unittests.gypi')
-  c.version_file = Path('[CHECKOUT]', 'syzygy', 'SYZYGY_VERSION')
+  c.unittests_gypi = c.CHECKOUT_PATH.join('syzygy', 'unittests.gypi')
+  c.version_file = c.CHECKOUT_PATH.join('syzygy', 'SYZYGY_VERSION')
 
 
 @config_ctx()
 def syzygy_official(c):
   c.official_build = True
-  c.unittests_gypi = Path('[CHECKOUT]', 'syzygy', 'unittests.gypi')
-  c.version_file = Path('[CHECKOUT]', 'syzygy', 'SYZYGY_VERSION')
+  c.unittests_gypi = c.CHECKOUT_PATH.join('syzygy', 'unittests.gypi')
+  c.version_file = c.CHECKOUT_PATH.join('syzygy', 'SYZYGY_VERSION')
 
 
 @config_ctx()
 def kasko_official(c):
   c.official_build = True
-  c.unittests_gypi = Path('[CHECKOUT]', 'syzygy', 'kasko', 'unittests.gypi')
-  c.version_file = Path('[CHECKOUT]', 'syzygy', 'kasko', 'VERSION')
+  c.unittests_gypi = c.CHECKOUT_PATH.join('syzygy', 'kasko', 'unittests.gypi')
+  c.version_file = c.CHECKOUT_PATH.join('syzygy', 'kasko', 'VERSION')