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

recipe_modules/depot_tools/api.py

Index: recipe_modules/depot_tools/api.py
diff --git a/recipe_modules/depot_tools/api.py b/recipe_modules/depot_tools/api.py
new file mode 100644
index 0000000000000000000000000000000000000000..3685330e9035d949d9101f999f89d68de89ed148
--- /dev/null
+++ b/recipe_modules/depot_tools/api.py
@@ -0,0 +1,12 @@
+# 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.
+
+"""Entry point for interacting with depot_tools from recipes."""
+
+from recipe_engine import recipe_api
+
+class DepotToolsApi(recipe_api.RecipeApi):
+  @property
+  def gclient_py(self):
+    return self.package_resource('gclient.py')