Make histogram_suffixes separators and enum labels required.

tools/metrics/actions/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 actions.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 = {
     'action': ['name', 'not_user_triggered'],
     'action-suffix': ['separator', 'ordering'],
     'actions': [],
     'actions-suffixes': [],
     'affected-action': ['name'],
     'description': [],
     'obsolete': [],
     'owner': [],
     'suffix': ['name', 'label'],
     'with-suffix': ['name'],
 }
 
+# Attribute names that must be explicitly specified on nodes that support them.
+REQUIRED_ATTRIBUTES = [
+    'label',
+    'name',
+    'separator',
+]
+
 # Tag names for top-level nodes whose children we don't want to indent.
 TAGS_THAT_DONT_INDENT = [
     'actions',
     'actions-suffixes',
 ]
 
 # Extra vertical spacing rules for special tag names.
 # {tag_name: (newlines_after_open, newlines_before_close, newlines_after_close)}
 TAGS_THAT_HAVE_EXTRA_NEWLINE = {
     'actions': (2, 1, 1),
@@ skipping 12 matching lines @@
 # and a key function that maps each child node to the desired sort key.
 TAGS_ALPHABETIZATION_RULES = {
     'actions': ('action', LOWERCASE_NAME_FN),
     'action-suffix': ('affected-action', LOWERCASE_NAME_FN),
 }
 
 
 def GetPrintStyle():
   """Returns an XmlStyle object for pretty printing actions."""
   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)