[Telemetry] Introduce SummarizableValue.

tools/telemetry/telemetry/value/scalar.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 numbers
 
 from telemetry import value as value_module
 from telemetry.value import list_of_scalar_values
 from telemetry.value import none_values
+from telemetry.value import summarizable
 
 
-class ScalarValue(value_module.Value):
+class ScalarValue(summarizable.SummarizableValue):
   def __init__(self, page, name, units, value, important=True,
                description=None, tir_label=None,
-               none_value_reason=None):
+               none_value_reason=None, improvement_direction=None):
     """A single value (float or integer) result from a test.
 
     A test that counts the number of DOM elements in a page might produce a
     scalar value:
        ScalarValue(page, 'num_dom_elements', 'count', num_elements)
     """
     super(ScalarValue, self).__init__(page, name, units, important, description,
-                                      tir_label)
+                                      tir_label, improvement_direction)
     assert value is None or isinstance(value, numbers.Number)
     none_values.ValidateNoneValueReason(value, none_value_reason)
     self.value = value
     self.none_value_reason = none_value_reason
 
   def __repr__(self):
     if self.page:
       page_name = self.page.display_name
     else:
       page_name = 'None'
     return ('ScalarValue(%s, %s, %s, %s, important=%s, description=%s, '
-            'tir_label=%s') % (
+            'tir_label=%s, improvement_direction=%s') % (
                 page_name,
                 self.name,
                 self.units,
                 self.value,
                 self.important,
                 self.description,
-                self.tir_label)
+                self.tir_label,
+                self.improvment_direction)
 
   def GetBuildbotDataType(self, output_context):
     if self._IsImportantGivenOutputIntent(output_context):
       return 'default'
     return 'unimportant'
 
   def GetBuildbotValue(self):
     # Buildbot's print_perf_results method likes to get lists for all values,
     # even when they are scalar, so list-ize the return value.
     return [self.value]
@@ skipping 14 matching lines @@
 
     if self.none_value_reason is not None:
       d['none_value_reason'] = self.none_value_reason
 
     return d
 
   @staticmethod
   def FromDict(value_dict, page_dict):
     kwargs = value_module.Value.GetConstructorKwArgs(value_dict, page_dict)
     kwargs['value'] = value_dict['value']
+    kwargs['improvement_direction'] = value_dict['improvement_direction']
 
     if 'none_value_reason' in value_dict:
       kwargs['none_value_reason'] = value_dict['none_value_reason']
     if 'tir_label' in value_dict:
       kwargs['tir_label'] = value_dict['tir_label']
 
     return ScalarValue(**kwargs)
 
   @classmethod
   def MergeLikeValuesFromSamePage(cls, values):
@@ skipping 11 matching lines @@
   def _MergeLikeValues(cls, values, page, name, tir_label):
     v0 = values[0]
     merged_value = [v.value for v in values]
     none_value_reason = None
     if None in merged_value:
       merged_value = None
       none_value_reason = none_values.MERGE_FAILURE_REASON
     return list_of_scalar_values.ListOfScalarValues(
         page, name, v0.units, merged_value, important=v0.important,
         tir_label=tir_label,
-        none_value_reason=none_value_reason)
+        none_value_reason=none_value_reason,
+        improvement_direction=v0.improvement_direction)