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

tools/perf/benchmarks/dom_perf.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 json
 import math
 import os
 
 from telemetry import benchmark
 from telemetry import page as page_module
 from telemetry.core import util
 from telemetry.page import page_set
 from telemetry.page import page_test
+from telemetry.value import improvement_direction
 from telemetry.value import merge_values
 from telemetry.value import scalar
 
 
 def _GeometricMean(values):
   """Compute a rounded geometric mean from an array of values."""
   if not values:
     return None
   # To avoid infinite value errors, make sure no value is less than 0.001.
   new_values = []
@@ skipping 24 matching lines @@
       def _IsDone():
         return tab.GetCookieByName('__domperf_finished') == '1'
       util.WaitFor(_IsDone, 600)
 
       data = json.loads(tab.EvaluateJavaScript('__domperf_result'))
       for suite in data['BenchmarkSuites']:
         # Skip benchmarks that we didn't actually run this time around.
         if len(suite['Benchmarks']) or suite['score']:
           results.AddValue(scalar.ScalarValue(
               results.current_page, '%s.%s' % (suite['name'], SCORE_TRACE_NAME),
-              SCORE_UNIT, suite['score'], important=False))
+              SCORE_UNIT, suite['score'], important=False,
+              improvement_direction=improvement_direction.UP))
     finally:
       tab.EvaluateJavaScript('document.cookie = "__domperf_finished=0"')
 
   def DidRunTest(self, browser, results):
     # Now give the geometric mean as the total for the combined runs.
     combined = merge_values.MergeLikeValuesFromDifferentPages(
         results.all_page_specific_values,
         group_by_name_suffix=True)
     combined_score = [x for x in combined if x.name == SCORE_TRACE_NAME][0]
     total = _GeometricMean(combined_score.values)
     results.AddSummaryValue(
         scalar.ScalarValue(None, 'Total.' + SCORE_TRACE_NAME, SCORE_UNIT,
-                           total))
+                           total,
+                           improvement_direction=improvement_direction.UP))
 
 
 @benchmark.Disabled('android', 'linux')
 class DomPerf(benchmark.Benchmark):
   """A suite of JavaScript benchmarks for exercising the browser's DOM.
 
   The final score is computed as the geometric mean of the individual results.
   Scores are not comparable across benchmark suite versions and higher scores
   means better performance: Bigger is better!"""
   test = _DomPerfMeasurement
@@ skipping 10 matching lines @@
       'Events',
       'Get+Elements',
       'GridSort',
       'Template'
     ]
     ps = page_set.PageSet(file_path=dom_perf_dir)
     for param in run_params:
       ps.AddUserStory(page_module.Page(
           'file://run.html?reportInJS=1&run=%s' % param, ps, ps.base_dir))
     return ps