Add sync_submodules builders on master.chromium.infra.

scripts/slave/recipes/infra/sync_submodules.py

Index: scripts/slave/recipes/infra/sync_submodules.py
diff --git a/scripts/slave/recipes/infra/sync_submodules.py b/scripts/slave/recipes/infra/sync_submodules.py
new file mode 100644
index 0000000000000000000000000000000000000000..0777c86040728eed09c406b5deae90854ccc2ce0
--- /dev/null
+++ b/scripts/slave/recipes/infra/sync_submodules.py
@@ -0,0 +1,22 @@
+# 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.
+
+DEPS = [
+  'sync_submodules',
+  'recipe_engine/properties',
+]
+
+
+DEFAULT_SOURCE_REPO = 'https://chromium.googlesource.com/chromium/src'
+
+
+def RunSteps(api):
+  source_repo = api.properties.get('source_repo', DEFAULT_SOURCE_REPO)
+  dest_repo = api.properties.get('dest_repo', source_repo + '/codesearch')
+
+  api.sync_submodules(source_repo, dest_repo)
+
+
+def GenTests(api):
+  yield api.test('basic')