[Clean-up] Add a PRESUBMIT.py script for the proximity_auth component.

components/proximity_auth/PRESUBMIT.py

Index: components/proximity_auth/PRESUBMIT.py
diff --git a/chrome/browser/chromeos/extensions/PRESUBMIT.py b/components/proximity_auth/PRESUBMIT.py
similarity index 69%
copy from chrome/browser/chromeos/extensions/PRESUBMIT.py
copy to components/proximity_auth/PRESUBMIT.py
index 627f282619ee419a6b37d4b3a5c4a727c6a4c211..bf46ab394cffbc836543732db05e5eefe19be0a8 100644
--- a/chrome/browser/chromeos/extensions/PRESUBMIT.py
+++ b/components/proximity_auth/PRESUBMIT.py
@@ -2,13 +2,11 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Presubmit script for extensions and apps.
+"""Top-level presubmit script for the proximity_auth component.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
 def CheckChangeOnUpload(input_api, output_api):
-  results = []
-  results += input_api.canned_checks.CheckPatchFormatted(input_api, output_api)
-  return results
+  return input_api.canned_checks.CheckPatchFormatted(input_api, output_api)