Add git_cl recipe module.

recipe_modules/git_cl/config.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 types
+
+from recipe_engine.config import config_item_context, ConfigGroup, BadConf
+from recipe_engine.config import Single
+from recipe_engine.config_types import Path
+
+def BaseConfig(**_kwargs):

[iannucci, 2016/04/29 18:55:20]

not convinced this is necessary (or desirable)

If you don't like api.path['checkout'] for some reason, I would probably even
prefer

  with api.step.context(cwd="something"):
    # steps

  (Would require adding cwd to context, but that's a very easy change).

Or even

  with api.path.cwd(some_path):
    # api.path['cwd'] == some_path
    # api.step would use `api.path['cwd']` as its cwd value.

[tandrii(chromium), 2016/04/29 19:04:43]

+1. It's not desirable. path['checkout'] would be sane default, but I really
love context idea - I actually already have it, so martiniss@ how you about you
land without it, and i'll add my patch on top.

[martiniss, 2016/04/29 19:26:48]

Ok, i'll just keep this as is for now.

[tandrii(chromium), 2016/05/02 14:14:48]

OOps, I re-invented the wheel. Now I've re-read what Robbie wrote. The

with api.path.cwd(repo_path):
  ...

makes total sense to me and I have nothing else to offer. Stephen, why does this
not work for you?

+  return ConfigGroup(
+    repo_location=Single(Path)
+  )
+
+config_ctx = config_item_context(BaseConfig)
+
+@config_ctx()
+def basic(c):
+  pass
+
+