[Cleanup] Clean up enum ordering code in extract_histograms.py

tools/metrics/histograms/extract_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.
 
 """Extract histogram names from the description XML file.
 
 For more information on the format of the XML file, which is self-documenting,
 see histograms.xml; however, here is a simple example to get you started. The
 XML below will generate the following five histograms:
 
@@ skipping 198 matching lines @@
       value_dict = {}
       int_value = int(int_tag.getAttribute('value'))
       if int_value in enum_dict['values']:
         logging.error('Duplicate enum value %d for enum %s', int_value, name)
         have_errors = True
         continue
       value_dict['label'] = int_tag.getAttribute('label')
       value_dict['summary'] = _JoinChildNodes(int_tag)
       enum_dict['values'][int_value] = value_dict
 
-    enum_items = sorted(enum_dict['values'].iteritems(), key=lambda i: i[0])
-    enum_int_values = list(i[0] for i in enum_items)
+    enum_int_values = sorted(enum_dict['values'].keys())
 
     last_int_value = None
     for int_tag in enum.getElementsByTagName('int'):
       int_value = int(int_tag.getAttribute('value'))
       if last_int_value is not None and int_value < last_int_value:
         logging.error('Enum %s int values %d and %d are not in numerical order',
                       name, last_int_value, int_value)
         have_errors = True
         left_item_index = bisect.bisect_left(enum_int_values, int_value)
         if left_item_index == 0:
           logging.warning('Insert value %d at the beginning', int_value)
         else:
-          left_int_value, left_value_dict = enum_items[left_item_index - 1]
+          left_int_value = enum_int_values[left_item_index - 1]
+          left_label = enum_dict['values'][left_int_value]
           logging.warning('Insert value %d after %d ("%s")',
-                          int_value, left_int_value, left_value_dict['label'])
+                          int_value, left_int_value, left_label)

[DmitrySkiba, 2017/04/14 22:01:41]

Previously it was logging just a string, but now left_label is actually a dict -
is this intentional?

[Ilya Sherman, 2017/04/14 22:31:26]

Whoops, not intentional, thanks.  Fixed.

       else:
         last_int_value = int_value
 
     summary_nodes = enum.getElementsByTagName('summary')
     if summary_nodes:
       enum_dict['summary'] = _NormalizeString(_JoinChildNodes(summary_nodes[0]))
 
     enums[name] = enum_dict
 
   return enums, have_errors
@@ skipping 278 matching lines @@
   with open(filename, 'r') as f:
     histograms, had_errors = ExtractHistogramsFromFile(f)
     if had_errors:
       logging.error('Error parsing %s', filename)
       raise Error()
     return histograms
 
 
 def ExtractNames(histograms):
   return sorted(histograms.keys())