Further reducing the max required samples.

scripts/slave/recipe_modules/auto_bisect/bisector.py

 # Copyright 2015 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 json
 import re
 import time
 import urllib
 
 from . import depot_config
@@ skipping 30 matching lines @@
 # When we look for the next revision to build, we search nearby revisions
 # looking for a revision that's already been archived. Since we don't want
 # to move *too* far from the original revision, we'll cap the search at 25%.
 DEFAULT_SEARCH_RANGE_PERCENTAGE = 0.25
 
 # How long to re-test the initial good-bad range for until significant
 # difference is established.
 REGRESSION_CHECK_TIMEOUT = 2 * 60 * 60
 # If we reach this number of samples on the reference range and have not
 # achieved statistical significance, bail.
-MAX_REQUIRED_SAMPLES = 25
+MAX_REQUIRED_SAMPLES = 15
 
 # Significance level to use for determining difference between revisions via
 # hypothesis testing.
 SIGNIFICANCE_LEVEL = 0.005
 
 _FAILED_INITIAL_CONFIDENCE_ABORT_REASON = (
     'The metric values for the initial "good" and "bad" revisions '
     'do not represent a clear regression.')
 
 _DIRECTION_OF_IMPROVEMENT_ABORT_REASON = (
@@ skipping 781 matching lines @@
         })
     return revision_rows
 
   def _get_build_url(self):
     properties = self.api.m.properties
     bot_url = properties.get('buildbotURL',
                              'http://build.chromium.org/p/chromium/')
     builder_name = urllib.quote(properties.get('buildername', ''))
     builder_number = str(properties.get('buildnumber', ''))
     return '%sbuilders/%s/builds/%s' % (bot_url, builder_name, builder_number)