Use a different algorithm with the low entropy source for field trials.

chrome/chrome_tests.gypi

 # Copyright (c) 2012 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.
 {
   'variables' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
       'common/pref_names.cc',
@@ skipping 1973 matching lines @@
         'common/json_pref_store_unittest.cc',
         'common/json_schema_validator_unittest.cc',
         'common/json_schema_validator_unittest_base.cc',
         'common/json_schema_validator_unittest_base.h',
         'common/json_value_serializer_unittest.cc',
         'common/mac/cfbundle_blocker_unittest.mm',
         'common/mac/mock_launchd.cc',
         'common/mac/mock_launchd.h',
         'common/mac/objc_method_swizzle_unittest.mm',
         'common/mac/objc_zombie_unittest.mm',
+        'common/metrics/entropy_provider_unittest.cc',
         'common/metrics/metrics_log_base_unittest.cc',
         'common/metrics/metrics_log_manager_unittest.cc',
         'common/metrics/variations/variations_util_unittest.cc',
         'common/multi_process_lock_unittest.cc',
         'common/net/url_util_unittest.cc',
         'common/net/gaia/gaia_auth_fetcher_unittest.cc',
         'common/net/gaia/gaia_auth_util_unittest.cc',
         'common/net/gaia/gaia_authenticator_unittest.cc',
         'common/net/gaia/gaia_oauth_client_unittest.cc',
         'common/net/gaia/google_service_auth_error_unittest.cc',
@@ skipping 2699 matching lines @@
                 '--result', '<@(_outputs)',
                 '--isolate', 'browser_tests.isolate',
               ],
             },
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }