Add fetch recipe for the open source infra repo.

recipes/infra.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 sys
+
+import recipe_util  # pylint: disable=F0401
+
+
+# This class doesn't need an __init__ method, so we disable the warning
+# pylint: disable=W0232
+class Infra(recipe_util.Recipe):
+  """Basic Recipe class for the Infrastructure repositories."""
+
+  @staticmethod
+  def fetch_spec(props):
+    url = 'https://chromium.googlesource.com/infra/infra.git'
+    solution = {
+        'name'     : 'infra',
+        'url'      : url,
+        'deps_file': 'DEPS',
+        'managed'  : False,
+    }
+    spec = {
+        'solutions': [solution],
+    }
+    return {
+        'type': 'gclient_git',
+        'gclient_git_spec': spec,
+    }
+
+  @staticmethod
+  def expected_root(_props):
+    return 'infra'
+
+
+def main(argv=None):
+  return Infra().handle_args(argv)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))