Revert of Remove now obsolete checkdeps copy

tools/checkdeps/PRESUBMIT.py

Index: tools/checkdeps/PRESUBMIT.py
diff --git a/tools/checkdeps/PRESUBMIT.py b/tools/checkdeps/PRESUBMIT.py
new file mode 100644
index 0000000000000000000000000000000000000000..10ef63212faebd6452d08353a202509b252fc908
--- /dev/null
+++ b/tools/checkdeps/PRESUBMIT.py
@@ -0,0 +1,25 @@
+# Copyright (c) 2012 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.
+
+"""Presubmit script for checkdeps tool.
+"""
+
+
+def CheckChange(input_api, output_api):
+  results = []
+  results.extend(input_api.canned_checks.RunUnitTests(
+      input_api, output_api,
+      [input_api.os_path.join(input_api.PresubmitLocalPath(),
+                              'checkdeps_test.py')]))
+  return results
+
+
+# Mandatory entrypoint.
+def CheckChangeOnUpload(input_api, output_api):
+  return CheckChange(input_api, output_api)
+
+
+# Mandatory entrypoint.
+def CheckChangeOnCommit(input_api, output_api):
+  return CheckChange(input_api, output_api)