Fix presubmit_scheme_histograms.py and presubmit_bad_message_reasons.py

content/browser/PRESUBMIT.py

 # Copyright 2017 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 to check that BadMessage enums in histograms.xml
 match the corresponding bad_message.h file.
 """
 
+def CheckChangeOnCommit(input_api, output_api):
+  return _CommonChecks(input_api, output_api)
+
+def CheckChangeOnUpload(input_api, output_api):
+  return _CommonChecks(input_api, output_api)
+

[Łukasz Anforowicz, 2017/04/26 22:20:54]

I don't understand why we have separate CheckChangeOnCommit and a separate
CheckChangeOnUpload.  Sometimes commit happens a little while after an upload
and it seems useful to have the same checks apply in both cases (in case
something landed recently that would have messed up the histogram enums).

I see that other presubmit scripts (i.e. the one in
//chrome/browser/PRESUBMIT.py) use the _CommonChecks pattern to work around
this.

 def _RunHistogramChecks(input_api, output_api, histogram_name):
   try:
     # Setup sys.path so that we can call histrogram code
     import sys
     original_sys_path = sys.path
     sys.path = sys.path + [input_api.os_path.join(
       input_api.change.RepositoryRoot(),
       'tools', 'metrics', 'histograms')]
 
     import presubmit_bad_message_reasons
     return presubmit_bad_message_reasons.PrecheckBadMessage(input_api,
       output_api, histogram_name)
   except Exception as e:
     return [output_api.PresubmitError("Error verifying histogram (%s)."
       % str(e))]
   finally:
     sys.path = original_sys_path
 
-def CheckChangeOnUpload(input_api, output_api):
+def _CommonChecks(input_api, output_api):
   return _RunHistogramChecks(input_api, output_api, "BadMessageReasonContent")