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

tools/perf/benchmarks/jetstream.py

Index: tools/perf/benchmarks/jetstream.py
diff --git a/tools/perf/benchmarks/jetstream.py b/tools/perf/benchmarks/jetstream.py
index 32b99f375300b417f515d424884a15d9cf9c0661..fdda21a0f0f0a2f177585cc2f15274cf24c05171 100644
--- a/tools/perf/benchmarks/jetstream.py
+++ b/tools/perf/benchmarks/jetstream.py
@@ -25,6 +25,7 @@ from telemetry import page as page_module
 from telemetry.page import page_set
 from telemetry.page import page_test
 from telemetry.util import statistics
+from telemetry.value import improvement_direction
 from telemetry.value import list_of_scalar_values
 
 
@@ -64,7 +65,7 @@ class _JetstreamMeasurement(page_test.PageTest):
     for k, v in result.iteritems():
       results.AddValue(list_of_scalar_values.ListOfScalarValues(
           results.current_page, k.replace('.', '_'), 'score', v['result'],
-          important=False))
+          important=False, improvement_direction=improvement_direction.UP))
       # Collect all test scores to compute geometric mean.
       for i, score in enumerate(v['result']):
         if len(all_score_lists) <= i:
@@ -74,7 +75,8 @@ class _JetstreamMeasurement(page_test.PageTest):
     for score_list in all_score_lists:
       all_scores.append(statistics.GeometricMean(score_list))
     results.AddSummaryValue(list_of_scalar_values.ListOfScalarValues(
-        None, 'Score', 'score', all_scores))
+        None, 'Score', 'score', all_scores,
+        improvement_direction=improvement_direction.UP))
 
 
 @benchmark.Disabled('android', 'xp')  # crbug.com/381742