Clean up histograms.xml formatting

tools/metrics/histograms/print_style.py

 # 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.
 
 """Holds the constants for pretty printing histograms.xml."""
 
 import os
 import sys
 
 # Import the metrics/common module for pretty print xml.
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
 import pretty_print_xml
 
 # Desired order for tag and tag attributes. The *_ATTRIBUTE_ORDER maps are also
 # used to determine the validity of tag names.
 # { tag_name: [attribute_name, ...] }
 ATTRIBUTE_ORDER = {
     'affected-histogram': ['name'],
     'details': [],
-    'enum': ['name', 'type'],
+    'enum': ['name'],
     'enums': [],
     'histogram': ['base', 'name', 'enum', 'units'],
     'histogram-configuration': ['logsource'],
-    'histogram_suffixes': ['name', 'separator', 'ordering'],
-    'histogram_suffixes_list': [],
+    'histogram-suffixes': ['name', 'separator', 'ordering'],
+    'histogram-suffixes-list': [],
     'histograms': [],
     'int': ['value', 'label'],
     'obsolete': [],
     'owner': [],
     'suffix': ['base', 'name', 'label'],
     'summary': [],
     'with-suffix': ['name'],
 }
 
+# Attribute names that must be explicitly specified on nodes that support them.
+REQUIRED_ATTRIBUTES = [
+    # TODO(isherman): Make the 'label' attribute required as well. This requires
+    # fixing up existing suffixes that omit a label.
+    'name',
+    'separator',
+    'value',
+]
+
 # Tag names for top-level nodes whose children we don't want to indent.
 TAGS_THAT_DONT_INDENT = [
     'histogram-configuration',
     'histograms',
-    'histogram_suffixes_list',
+    'histogram-suffixes-list',
     'enums',
 ]
 
 # Extra vertical spacing rules for special tag names.
 # {tag_name: (newlines_after_open, newlines_before_close, newlines_after_close)}
 TAGS_THAT_HAVE_EXTRA_NEWLINE = {
     'histogram-configuration': (2, 1, 1),
     'histograms': (2, 1, 1),
-    'histogram_suffixes_list': (2, 1, 1),
-    'histogram_suffixes': (1, 1, 1),
+    'histogram-suffixes-list': (2, 1, 1),
+    'histogram-suffixes': (1, 1, 1),
     'enums': (2, 1, 1),
     'histogram': (1, 1, 1),
     'enum': (1, 1, 1),
 }
 
 # Tags that we allow to be squished into a single line for brevity.
 TAGS_THAT_ALLOW_SINGLE_LINE = ['summary', 'int', 'owner']
 
 LOWERCASE_NAME_FN = lambda n: n.attributes['name'].value.lower()
 
 # Tags whose children we want to alphabetize. The key is the parent tag name,
 # and the value is a pair of the tag name of the children we want to sort,
 # and a key function that maps each child node to the desired sort key.
 TAGS_ALPHABETIZATION_RULES = {
     'histograms': ('histogram', LOWERCASE_NAME_FN),
     'enums': ('enum', LOWERCASE_NAME_FN),
     'enum': ('int', lambda n: int(n.attributes['value'].value)),
-    'histogram_suffixes_list': ('histogram_suffixes', LOWERCASE_NAME_FN),
-    'histogram_suffixes': ('affected-histogram', LOWERCASE_NAME_FN),
+    'histogram-suffixes-list': ('histogram-suffixes', LOWERCASE_NAME_FN),
+    'histogram-suffixes': ('affected-histogram', LOWERCASE_NAME_FN),
 }
 
 
 def GetPrintStyle():
   """Returns an XmlStyle object for pretty printing histograms."""
   return pretty_print_xml.XmlStyle(ATTRIBUTE_ORDER,
+                                   REQUIRED_ATTRIBUTES,
                                    TAGS_THAT_HAVE_EXTRA_NEWLINE,
                                    TAGS_THAT_DONT_INDENT,
                                    TAGS_THAT_ALLOW_SINGLE_LINE,
                                    TAGS_ALPHABETIZATION_RULES)