Added support for improvement_direction to relevant values, which is propogated to chartjson.

tools/perf/metrics/media.py

 # Copyright 2013 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.
 import logging
 import os
 
 from metrics import Metric
+from telemetry.value import improvement_direction
 from telemetry.value import list_of_scalar_values
 from telemetry.value import scalar
 
 
 class MediaMetric(Metric):
   """MediaMetric class injects and calls JS responsible for recording metrics.
 
   Default media metrics are collected for every media element in the page,
   such as decoded_frame_count, dropped_frame_count, decoded_video_bytes, and
   decoded_audio_bytes.
@@ skipping 34 matching lines @@
     Media metrics contain an ID identifying the media element and values:
     media_metric = {
       'id': 'video_1',
       'metrics': {
           'time_to_play': 120,
           'decoded_bytes': 13233,
           ...
       }
     }
     """
-    def AddOneResult(metric, unit):
+    def AddOneResult(metric, unit, direction):
       if metric in exclude_metrics:
         return
 
       metrics = media_metric['metrics']
       for m in metrics:
         if m.startswith(metric):
           special_label = m[len(metric):]
           trace_name = '%s.%s%s' % (metric, trace, special_label)
           if isinstance(metrics[m], list):
             results.AddValue(list_of_scalar_values.ListOfScalarValues(
                 results.current_page, trace_name, unit,
                 values=[float(v) for v in metrics[m]],
-                important=True))
+                important=True, improvement_direction=direction))
           else:
             results.AddValue(scalar.ScalarValue(
                 results.current_page, trace_name, unit, value=float(metrics[m]),
-                important=True))
+                important=True, improvement_direction=direction))
 
     trace = media_metric['id']
     if not trace:
       logging.error('Metrics ID is missing in results.')
       return
 
     if not self._skip_basic_metrics:
-      AddOneResult('buffering_time', 'ms')
-      AddOneResult('decoded_audio_bytes', 'bytes')
-      AddOneResult('decoded_video_bytes', 'bytes')
-      AddOneResult('decoded_frame_count', 'frames')
-      AddOneResult('dropped_frame_count', 'frames')
-      AddOneResult('time_to_play', 'ms')
+      AddOneResult('buffering_time', 'ms', improvement_direction.DOWN)
+      AddOneResult('decoded_audio_bytes', 'bytes', improvement_direction.DOWN)
+      AddOneResult('decoded_video_bytes', 'bytes', improvement_direction.DOWN)
+      AddOneResult('decoded_frame_count', 'frames', improvement_direction.DOWN)
+      AddOneResult('dropped_frame_count', 'frames', improvement_direction.DOWN)
+      AddOneResult('time_to_play', 'ms', improvement_direction.DOWN)
 
-    AddOneResult('avg_loop_time', 'ms')
-    AddOneResult('seek', 'ms')
+    AddOneResult('avg_loop_time', 'ms', improvement_direction.DOWN)
+    AddOneResult('seek', 'ms', improvement_direction.DOWN)
     return trace