[Telemetry] Make "discard_first_result" apply to user_stories too.

tools/perf/benchmarks/startup.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.
 
 from measurements import startup
 import page_sets
 from telemetry import benchmark
 
 
 class _StartupCold(benchmark.Benchmark):
   """Measures cold startup time with a clean profile."""
   options = {'pageset_repeat': 5}
 
   @classmethod
   def Name(cls):
     return 'startup'
 
   def CreatePageTest(self, options):
     return startup.Startup(cold=True)
 
 
 class _StartupWarm(benchmark.Benchmark):
   """Measures warm startup time with a clean profile."""
   options = {'pageset_repeat': 20}
 
   @classmethod
   def Name(cls):
     return 'startup'
 
+  @classmethod
+  def ValueCanBeAddedPredicate(cls, _, is_first_result):
+    return not is_first_result
+
   def CreatePageTest(self, options):
     return startup.Startup(cold=False)
 
 
 @benchmark.Enabled('has tabs')
 @benchmark.Disabled('snowleopard') # crbug.com/336913
 class StartupColdBlankPage(_StartupCold):
   """Measures cold startup time with a clean profile."""
   tag = 'cold'
   page_set = page_sets.BlankPageSet
 
   @classmethod
   def Name(cls):
     return 'startup.cold.blank_page'
 
 
 @benchmark.Enabled('has tabs')
 class StartupWarmBlankPage(_StartupWarm):
   """Measures warm startup time with a clean profile."""
   tag = 'warm'
   page_set = page_sets.BlankPageSet
 
   @classmethod
   def Name(cls):
     return 'startup.warm.blank_page'