Set up depot_tools as a recipe package, and add depot_tools recipe module.

recipe_modules/depot_tools/example.py

Index: recipe_modules/depot_tools/example.py
diff --git a/recipe_modules/depot_tools/example.py b/recipe_modules/depot_tools/example.py
new file mode 100644
index 0000000000000000000000000000000000000000..4afa8e8ee7c01611eea5430343e73c2a5c6de40e
--- /dev/null
+++ b/recipe_modules/depot_tools/example.py
@@ -0,0 +1,14 @@
+# Copyright (c) 2015 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.
+
+DEPS = [
+  'recipe_engine/python',
+  'depot_tools',
+]
+
+def RunSteps(api):
+  api.python('gclient help', api.depot_tools.gclient_py, ['--help'])
+
+def GenTests(api):
+  yield api.test('basic')