Display telemetry chartjson output and result data on waterfall.

scripts/slave/telemetry_utils.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.
 # pylint: disable=R0201
 
 """Log parsing for telemetry tests.
 
 The TelemetryResultsProcessor loads and contains results that were output in
 JSON format from Telemetry. It can be used as a replacement for the classes in
 the performance_log_processor module.
 """
 
 import json
 import logging
 import os
 
+from slave.performance_log_processor import _FormatHumanReadable
+
+
 class TelemetryResultsProcessor(object):
 
   def __init__(self, filename, is_ref):
     self._chart_filename = filename
     self._is_reference_build = is_ref
 
   def ChartJson(self):
     try:
       return json.load(open(self._chart_filename))
     except (IOError, ValueError):
@@ skipping 26 matching lines @@
   def FailedTests(self):
     return []
 
   def SuppressionHashes(self):  # pylint: disable=R0201
     return []
 
   def ParsingErrors(self):  # pylint: disable=R0201
     return []
 
   def PerformanceSummary(self):
-    return ''
+    """Writes the waterfall display text.
+
+    The waterfall contains lines for each important trace, in the form
+      tracename: value< (refvalue)>
+    """
+    if self._is_reference_build:
+      return []
+
+    results = []
+    for chart_name, chart_values in self.ChartJson()['charts'].iteritems():
+      if 'summary' in chart_values:
+        summary = chart_values['summary']
+        if summary['important']:
+          mean = sum(summary['values']) / float(len(summary['values']))
+          display = '%s: %s' % (chart_name, _FormatHumanReadable(mean))
+          results.append(display)
+    return results