[Telemetry] Introduce SummarizableValue.

tools/telemetry/telemetry/value/summarizable.py

+# Copyright 2014 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.
+
+from telemetry import value as value_module
+
+
+class SummarizableValue(value_module.Value):
+  def __init__(self, page, name, units, important, description, tir_label,
+               improvement_direction):
+    """A summarizable value result from a test."""
+    super(SummarizableValue, self).__init__(
+        page, name, units, important, description, tir_label)
+# TODO(eakuefner): uncomment this assert after Telemetry clients are fixed.
+# Note: Telemetry unittests satisfy this assert.
+#    assert improvement_direction_module.IsValid(improvement_direction)
+    self._improvement_direction = improvement_direction
+
+  @property
+  def improvement_direction(self):
+    return self._improvement_direction
+
+  def AsDict(self):
+    d = super(SummarizableValue, self).AsDict()
+    d['improvement_direction'] = self.improvement_direction
+    return d
+
+  @staticmethod
+  def GetJSONTypeName():
+    return 'summarizable'
+
+  def AsDictWithoutBaseClassEntries(self):
+    d = super(SummarizableValue, self).AsDictWithoutBaseClassEntries()
+    del d['improvement_direction']
+    return d
+
+  def GetBuildbotDataType(self, output_context):
+    """Returns the buildbot's equivalent data_type.
+
+    This should be one of the values accepted by perf_tests_results_helper.py.
+    """
+    raise NotImplementedError()
+
+  def GetBuildbotValue(self):
+    """Returns the buildbot's equivalent value."""
+    raise NotImplementedError()
+
+  @classmethod
+  def MergeLikeValuesFromSamePage(cls, values):
+    raise NotImplementedError()
+
+  @classmethod
+  def MergeLikeValuesFromDifferentPages(cls, values):
+    raise NotImplementedError()
+
+  def GetRepresentativeNumber(self):
+    """Gets a single scalar value that best-represents this value.
+
+    Returns None if not possible.
+    """
+    raise NotImplementedError()
+
+  def GetRepresentativeString(self):
+    """Gets a string value that best-represents this value.
+
+    Returns None if not possible.
+    """
+    raise NotImplementedError()