Add git cl format presubmit warning for extension and apps.

chrome/browser/extensions/PRESUBMIT.py

 # 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.
 
 """Chromium presubmit script for src/chrome/browser/extensions.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details on the presubmit API built into gcl.
 """
 
@@ skipping 279 matching lines @@
     self.PerformChecks(affected_file)
     self.LogInfo("Done processing file \"%s\"" % affected_file.LocalPath())
 
   def Run(self):
     for file in self.input_api.AffectedFiles(include_deletes=True):
       if file.LocalPath() == self.LOCAL_PATH:
         self.ProcessHistogramValueFile(file)
     return self.results
 
 def CheckChangeOnUpload(input_api, output_api):
-    results = []
-    results += HistogramValueChecker(input_api, output_api).Run()
-    return results
+  results = []
+  results += HistogramValueChecker(input_api, output_api).Run()
+  results += input_api.canned_checks.CheckPatchFormatted(input_api, output_api)
+  return results