Create metric_tool to deal with metric definitions

infra/tools/metric_tool/test/data/missing_descriptions.py

+# Copyright 2015 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.
+
+"""Example containing metrics with and without descriptions."""
+from infra_libs import ts_mon
+
+metric1 = ts_mon.BooleanMetric('/my/metric1', description='metric1')
+metric2 = ts_mon.CounterMetric('/my/metric2', description='metric2')
+metric3 = ts_mon.CumulativeDistributionMetric('/my/metric3',
+                                              description='metric3')
+metric4 = ts_mon.CumulativeMetric('/my/metric4', description='metric4')
+
+metric6 = ts_mon.FloatMetric('/my/metric6')
+metric7 = ts_mon.GaugeMetric('/my/metric7')
+metric8 = ts_mon.CumulativeDistributionMetric('/my/metric8')
+metric9 = ts_mon.NonCumulativeDistributionMetric('/my/metric9')
+metric10 = ts_mon.StringMetric('/my/metric10')