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

tools/telemetry/telemetry/value/failure.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.
 
 import sys
 import traceback
 
 from telemetry import value as value_module
 
 
@@ skipping 63 matching lines @@
   def AsDict(self):
     d = super(FailureValue, self).AsDict()
     d['value'] = GetStringFromExcInfo(self.exc_info)
     return d
 
   @staticmethod
   def FromDict(value_dict, page_dict):
     kwargs = value_module.Value.GetConstructorKwArgs(value_dict, page_dict)
     del kwargs['name']
     del kwargs['units']
-    important = kwargs.get('important', None)
-    if important != None:
+    if 'important' in kwargs:
       del kwargs['important']
+    if 'higher_is_better' in kwargs:
+      del kwargs['higher_is_better']
     kwargs['exc_info'] = FailureValue._GetExcInfoFromMessage(
         value_dict['value'])
 
     return FailureValue(**kwargs)
 
   @classmethod
   def MergeLikeValuesFromSamePage(cls, values):
     assert False, 'Should not be called.'
 
   @classmethod
   def MergeLikeValuesFromDifferentPages(cls, values,
                                         group_by_name_suffix=False):
     assert False, 'Should not be called.'
 
 def GetStringFromExcInfo(exc_info):
   return ''.join(traceback.format_exception(*exc_info))