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

tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py

Index: tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py
diff --git a/tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py b/tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py
index 5e07b960228328b654d86bec85e824ee85e53348..899341e699d8e434d7f9d1f1448e9f0f83a5b9d7 100644
--- a/tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py
+++ b/tools/telemetry/telemetry/web_perf/timeline_based_measurement_unittest.py
@@ -16,6 +16,7 @@ from telemetry.timeline import async_slice
 from telemetry.unittest_util import browser_test_case
 from telemetry.unittest_util import options_for_unittests
 from telemetry.unittest_util import page_test_test_case
+from telemetry.value import improvement_direction
 from telemetry.value import scalar
 from telemetry.web_perf import timeline_based_measurement as tbm_module
 from telemetry.web_perf import timeline_interaction_record as tir_module
@@ -26,30 +27,36 @@ class FakeFastMetric(timeline_based_metric.TimelineBasedMetric):
 
   def AddResults(self, model, renderer_thread, interaction_records, results):
     results.AddValue(scalar.ScalarValue(
-        results.current_page, 'FakeFastMetric', 'ms', 1))
+        results.current_page, 'FakeFastMetric', 'ms', 1,
+        improvement_direction=improvement_direction.DOWN))
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'FastMetricRecords', 'count',
-        len(interaction_records)))
+        len(interaction_records),
+        improvement_direction=improvement_direction.DOWN))
 
 
 class FakeSmoothMetric(timeline_based_metric.TimelineBasedMetric):
 
   def AddResults(self, model, renderer_thread, interaction_records, results):
     results.AddValue(scalar.ScalarValue(
-        results.current_page, 'FakeSmoothMetric', 'ms', 1))
+        results.current_page, 'FakeSmoothMetric', 'ms', 1,
+        improvement_direction=improvement_direction.DOWN))
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'SmoothMetricRecords', 'count',
-        len(interaction_records)))
+        len(interaction_records),
+        improvement_direction=improvement_direction.DOWN))
 
 
 class FakeLoadingMetric(timeline_based_metric.TimelineBasedMetric):
 
   def AddResults(self, model, renderer_thread, interaction_records, results):
     results.AddValue(scalar.ScalarValue(
-        results.current_page, 'FakeLoadingMetric', 'ms', 2))
+        results.current_page, 'FakeLoadingMetric', 'ms', 2,
+        improvement_direction=improvement_direction.DOWN))
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'LoadingMetricRecords', 'count',
-        len(interaction_records)))
+        len(interaction_records),
+        improvement_direction=improvement_direction.DOWN))
 
 
 def GetMetricFromMetricType(metric_type):