depot_tools: add infra_paths recipe module for infra-specific paths (attempt #2)

recipe_modules/infra_paths/api.py

Index: recipe_modules/infra_paths/api.py
diff --git a/recipe_modules/infra_paths/api.py b/recipe_modules/infra_paths/api.py
new file mode 100644
index 0000000000000000000000000000000000000000..cad3f28b440153669727d5b78ccece57c97af2ca
--- /dev/null
+++ b/recipe_modules/infra_paths/api.py
@@ -0,0 +1,12 @@
+# Copyright 2016 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 recipe_engine import recipe_api
+
+
+class InfraPathsApi(recipe_api.RecipeApi):
+  def initialize(self):
+    # TODO(phajdan.jr): remove dupes from the engine and delete infra_ prefix.
+    self.m.path.set_config(
+        'infra_' + self.m.properties.get('path_config', 'buildbot'))