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

tools/telemetry/telemetry/value/list_of_scalar_values.py

Index: tools/telemetry/telemetry/value/list_of_scalar_values.py
diff --git a/tools/telemetry/telemetry/value/list_of_scalar_values.py b/tools/telemetry/telemetry/value/list_of_scalar_values.py
index 698957ad571e6a73aaf48d0b20572788af9af4f6..65a7fc394ce97aaea6758a7dfb64009a75b39ced 100644
--- a/tools/telemetry/telemetry/value/list_of_scalar_values.py
+++ b/tools/telemetry/telemetry/value/list_of_scalar_values.py
@@ -15,9 +15,11 @@ def _Mean(values):
 class ListOfScalarValues(value_module.Value):
   def __init__(self, page, name, units, values,
                important=True, description=None, none_value_reason=None,
-               same_page_merge_policy=value_module.CONCATENATE):
+               same_page_merge_policy=value_module.CONCATENATE,
+               higher_is_better=None):
     super(ListOfScalarValues, self).__init__(page, name, units, important,
-                                             description)
+                                             description,
+                                             higher_is_better=higher_is_better)
     if values is not None:
       assert isinstance(values, list)
       assert len(values) > 0
@@ -37,14 +39,16 @@ class ListOfScalarValues(value_module.Value):
     else:
       merge_policy = 'PICK_FIRST'
     return ('ListOfScalarValues(%s, %s, %s, %s, '
-            'important=%s, description=%s, same_page_merge_policy=%s)') % (
+            'important=%s, description=%s, same_page_merge_policy=%s, '
+            'higher_is_better=%s)') % (
               page_name,
               self.name,
               self.units,
               repr(self.values),
               self.important,
               self.description,
-              merge_policy)
+              merge_policy,
+              self.higher_is_better)
 
   def GetBuildbotDataType(self, output_context):
     if self._IsImportantGivenOutputIntent(output_context):
@@ -98,7 +102,8 @@ class ListOfScalarValues(value_module.Value):
           values[0].values,
           important=v0.important,
           same_page_merge_policy=v0.same_page_merge_policy,
-          none_value_reason=v0.none_value_reason)
+          none_value_reason=v0.none_value_reason,
+          higher_is_better=v0.higher_is_better)
 
     assert v0.same_page_merge_policy == value_module.CONCATENATE
     return cls._MergeLikeValues(values, v0.page, v0.name)
@@ -127,4 +132,5 @@ class ListOfScalarValues(value_module.Value):
         merged_values,
         important=v0.important,
         same_page_merge_policy=v0.same_page_merge_policy,
-        none_value_reason=none_value_reason)
+        none_value_reason=none_value_reason,
+        higher_is_better=v0.higher_is_better)