Add Configurable metric_name_prefix

infra_libs/ts_mon/common/metrics.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.
 
 """Classes representing individual metrics that can be sent."""
 
 import copy
 
 from infra_libs.ts_mon.protos import metrics_pb2
 
@@ skipping 76 matching lines @@
     """Generate metrics_pb2.MetricsData messages for this metric.
 
     Args:
       collection_pb (metrics_pb2.MetricsCollection): protocol buffer into which
         to add the current metric values.
       start_time (int): timestamp in microseconds since UNIX epoch.
       target (Target): a Target to use.
     """
 
     metric_pb = collection_pb.data.add()
-    metric_pb.metric_name_prefix = '/chrome/infra/'
+    metric_pb.metric_name_prefix = interface.state.metric_name_prefix
     metric_pb.name = self._name
     if self._description is not None:
       metric_pb.description = self._description
 
     self._populate_value(metric_pb, value, start_time)
     self._populate_fields(metric_pb, fields)
 
     target._populate_target_pb(metric_pb)
 
   def _populate_fields(self, metric, fields):
@@ skipping 346 matching lines @@
                description=None):
     super(NonCumulativeDistributionMetric, self).__init__(
         name,
         is_cumulative=False,
         bucketer=bucketer,
         fields=fields,
         description=description)
 
   def is_cumulative(self):
     return False