Histograms.xml python script housekeeping

tools/metrics/histograms/update_net_error_codes.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Updates NetErrorCodes enum in histograms.xml file with values read
  from net_error_list.h.
 
 If the file was pretty-printed, the updated version is pretty-printed too.
 """
 
 import os.path
 import re
 import sys
 
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
-from update_histogram_enum import UpdateHistogramFromDict
+import histograms_path
+import update_histogram_enum
 
-NET_ERROR_LIST_PATH = '../../../net/base/net_error_list.h'
+NET_ERROR_LIST_PATH = 'net/base/net_error_list.h'
 
 POSITIVE_ERROR_REGEX = re.compile(r'^NET_ERROR\(([\w]+), -([0-9]+)\)')
 NEGATIVE_ERROR_REGEX = re.compile(r'^NET_ERROR\(([\w]+), (-[0-9]+)\)')
 
 def ReadNetErrorCodes(filename, error_regex):
   """Reads in values from net_error_list.h, returning a dictionary mapping
   error code to error name.
   """
   # Read the file as a list of lines
-  with open(filename) as f:
+  with open(histograms_path.GetInputFile(filename)) as f:
     content = f.readlines()
 
   # Parse out lines that are net errors.
   errors = {}
   for line in content:
     m = error_regex.match(line)
     if m:
       errors[int(m.group(2))] = m.group(1)
   return errors
 
 def main():
   if len(sys.argv) > 1:
     print >>sys.stderr, 'No arguments expected!'
     sys.stderr.write(__doc__)
     sys.exit(1)
 
-  UpdateHistogramFromDict(
+  update_histogram_enum.UpdateHistogramFromDict(
     'NetErrorCodes',
     ReadNetErrorCodes(NET_ERROR_LIST_PATH, POSITIVE_ERROR_REGEX),
     NET_ERROR_LIST_PATH)
 
-  UpdateHistogramFromDict(
+  update_histogram_enum.UpdateHistogramFromDict(
     'CombinedHttpResponseAndNetErrorCode',
     ReadNetErrorCodes(NET_ERROR_LIST_PATH, NEGATIVE_ERROR_REGEX),
     NET_ERROR_LIST_PATH)
 
 if __name__ == '__main__':
   main()