Script to populate the XML for the CSS property UseCounter.

tools/metrics/histograms/update_use_counter_css.py

Index: tools/metrics/histograms/update_use_counter_css.py
diff --git a/tools/metrics/histograms/update_use_counter_css.py b/tools/metrics/histograms/update_use_counter_css.py
new file mode 100755
index 0000000000000000000000000000000000000000..e20bee8a815021297533ce4f576412f0e319fa5f
--- /dev/null
+++ b/tools/metrics/histograms/update_use_counter_css.py
@@ -0,0 +1,71 @@
+#!/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.
+
+"""Scans the Chromium source of UseCounter, formats the Feature enum for
+histograms.xml and merges it. This script can also generate a python code
+snippet to put in uma.py of Chromium Dashboard. Make sure that you review the
+output for correctness.
+"""
+
+import optparse
+import os
+import re
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
+from update_histogram_enum import ReadHistogramValues
+from update_histogram_enum import UpdateHistogramFromDict
+from update_use_counter_feature_enum import PrintEnumForDashboard
+
+
+USE_COUNTER_CPP_PATH = \
+    '../../../third_party/WebKit/Source/core/frame/UseCounter.cpp'
+
+
+def EnumToCssProperty(enum_name):
+  """Converts a camel cased enum name to the lower case CSS property."""
+  # The first group also searches for uppercase letters to account for single
+  # uppercase letters, such as in "ZIndex" that need to convert to "z-index".
+  return re.sub(r'([a-zA-Z])([A-Z])', r'\1-\2', enum_name).lower()
+
+
+def ReadCssProperties(filename):
+  # Read the file as a list of lines
+  with open(filename) as f:
+    content = f.readlines()
+
+  # Looking for a line like "case CSSPropertyGrid: return 453;".
+  ENUM_REGEX = re.compile(r"""CSSProperty(.*):  # capture the enum name
+                              \s*return\s*
+                              ([0-9]+)          # capture the id
+                              """, re.VERBOSE)
+
+  properties = {}
+  for line in content:
+    enum_match = ENUM_REGEX.search(line)
+    if enum_match:
+      enum_name = enum_match.group(1)
+      property_id = int(enum_match.group(2))
+      properties[property_id] = EnumToCssProperty(enum_name)
+
+  return properties
+
+
+if __name__ == '__main__':
+  parser = optparse.OptionParser()
+  parser.add_option('--for-dashboard', action='store_true', dest='dashboard',
+                    default=False,
+                    help='Print enum definition formatted for use in uma.py of '
+                    'Chromium dashboard developed at '
+                    'https://github.com/GoogleChrome/chromium-dashboard')
+  options, args = parser.parse_args()
+
+  if options.dashboard:
+    enum_dict = ReadCssProperties(USE_COUNTER_CPP_PATH)
+    PrintEnumForDashboard(enum_dict)
+  else:
+    UpdateHistogramFromDict(
+        'MappedCSSProperties', ReadCssProperties(USE_COUNTER_CPP_PATH),
+        USE_COUNTER_CPP_PATH)