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

tools/perf/benchmarks/robohornet_pro.py

 # Copyright 2012 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.
 
 """Runs Microsoft's RoboHornet Pro benchmark."""
 
 import os
 
 from metrics import power
 from telemetry import benchmark
 from telemetry import page as page_module
 from telemetry.page import page_set
 from telemetry.page import page_test
+from telemetry.value import improvement_direction
 from telemetry.value import scalar
 
 
 class _RobohornetProMeasurement(page_test.PageTest):
   def __init__(self):
     super(_RobohornetProMeasurement, self).__init__(
         action_name_to_run='RunPageInteractions')
     self._power_metric = None
 
   def CustomizeBrowserOptions(self, options):
     power.PowerMetric.CustomizeBrowserOptions(options)
 
   def WillStartBrowser(self, platform):
     self._power_metric = power.PowerMetric(platform)
 
   def DidNavigateToPage(self, page, tab):
     self._power_metric.Start(page, tab)
 
   def ValidateAndMeasurePage(self, page, tab, results):
     tab.ExecuteJavaScript('ToggleRoboHornet()')
     tab.WaitForJavaScriptExpression(
         'document.getElementById("results").innerHTML.indexOf("Total") != -1',
         600)
 
     self._power_metric.Stop(page, tab)
     self._power_metric.AddResults(tab, results)
 
     result = int(tab.EvaluateJavaScript('stopTime - startTime'))
     results.AddValue(
-        scalar.ScalarValue(results.current_page, 'Total', 'ms', result))
+        scalar.ScalarValue(results.current_page, 'Total', 'ms', result,
+                           improvement_direction=improvement_direction.DOWN))
 
 
 # We plan to remove this test because it doesn't give useful data, but
 # we need to wait until Chrome OS can implement support for more helpful
 # benchmarks.
 @benchmark.Enabled('chromeos')
 class RobohornetPro(benchmark.Benchmark):
   """Milliseconds to complete the RoboHornetPro demo by Microsoft.
 
   http://ie.microsoft.com/testdrive/performance/robohornetpro/
   """
   test = _RobohornetProMeasurement
 
   def CreatePageSet(self, options):
     ps = page_set.PageSet(
         archive_data_file='../page_sets/data/robohornet_pro.json',
         file_path=os.path.abspath(__file__),
         bucket=page_set.PARTNER_BUCKET)
     ps.AddUserStory(page_module.Page(
         'http://ie.microsoft.com/testdrive/performance/robohornetpro/',
         ps, ps.base_dir,
         # Measurement require use of real Date.now() for measurement.
         make_javascript_deterministic=False))
     return ps