Histograms.xml python script housekeeping

tools/metrics/histograms/find_unmapped_histograms.py

 # Copyright 2013 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.
 
 """Scans the Chromium source for histograms that are absent from histograms.xml.
 
 This is a heuristic scan, so a clean run of this script does not guarantee that
 all histograms in the Chromium source are properly mapped.  Notably, field
 trials are entirely ignored by this script.
 
@@ skipping 112 matching lines @@
                   histogram)
 
 
 def readChromiumHistograms():
   """Searches the Chromium source for all histogram names.
 
   Also prints warnings for any invocations of the UMA_HISTOGRAM_* macros with
   names that might vary during a single run of the app.
 
   Returns:
-    A set cotaining any found literal histogram names.
+    A set containing any found literal histogram names.
   """
   logging.info('Scanning Chromium source for histograms...')
 
   # Use git grep to find all invocations of the UMA_HISTOGRAM_* macros.
   # Examples:
   #   'path/to/foo.cc:420:  UMA_HISTOGRAM_COUNTS_100("FooGroup.FooName",'
   #   'path/to/bar.cc:632:  UMA_HISTOGRAM_ENUMERATION('
   locations = commands.getoutput('git gs UMA_HISTOGRAM').split('\n')
   filenames = set([location.split(':')[0] for location in locations])
 
@@ skipping 103 matching lines @@
     logging.info('Histograms in Chromium but not in XML files:')
     logging.info('-------------------------------------------------')
     for histogram in sorted(unmapped_histograms):
       logging.info('  %s - %s', histogram, hashHistogramName(histogram))
   else:
     logging.info('Success!  No unmapped histograms found.')
 
 
 if __name__ == '__main__':
   main()