Metrics: Add a script to print out histogram ownership.

NOTRY=true

Review URL: https://codereview.chromium.org/456943002

Cr-Commit-Position: refs/heads/master@{#288484}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288484 0039d316-1c4b-4281-b951-d872f2087c98

tools/metrics/histograms/histogram_ownership.py

+#!/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.
+
+"""A simple tool to go through histograms.xml and print out the owners for
+histograms.
+"""
+
+import xml.etree.ElementTree
+
+DUMMY_OWNER = "Please list the metric's owners. Add more owner tags as needed."
+
+def main():
+  tree = xml.etree.ElementTree.parse('histograms.xml')
+  root = tree.getroot()
+  assert root.tag == 'histogram-configuration'
+
+  root_children = root.getchildren()
+  histograms = None
+  for node in root_children:
+    if node.tag == 'histograms':
+      histograms = node
+      break
+  assert histograms != None
+
+  for histogram in histograms.getchildren():
+    if histogram.tag != 'histogram':
+      continue
+
+    name = histogram.attrib['name']
+    owners = []
+    obsolete = False
+    for node in histogram.getchildren():
+      if node.tag == 'obsolete':
+        obsolete = True
+        continue
+      if node.tag != 'owner':
+        continue
+      if node.text == DUMMY_OWNER:
+        continue
+      assert '@' in node.text
+      owners.append(node.text)
+
+    if not obsolete:
+      if owners:
+        print name, ' '.join(owners)
+      else:
+        print name, 'NO_OWNER'
+
+if __name__ == '__main__':
+  main()