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

chrome/browser/chrome_browser_main.cc

 // 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.
 
 #include "chrome/browser/chrome_browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 529 matching lines @@
 #endif  // defined(OS_WIN)
 
   // Initialize FieldTrialList to support FieldTrials that use one-time
   // randomization.
   MetricsService* metrics = browser_process_->metrics_service();
   bool metrics_reporting_enabled = IsMetricsReportingEnabled();
   if (metrics_reporting_enabled)
     metrics->ForceClientIdCreation();  // Needed below.
   field_trial_list_.reset(
       new base::FieldTrialList(
-          metrics->GetEntropySource(metrics_reporting_enabled)));
+          metrics->CreateEntropyProvider(metrics_reporting_enabled).release()));
 
   // Ensure any field trials specified on the command line are initialized.
   // Also stop the metrics service so that we don't pollute UMA.
 #ifndef NDEBUG
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kForceFieldTrials)) {
     std::string persistent = command_line->GetSwitchValueASCII(
         switches::kForceFieldTrials);
     bool ret = base::FieldTrialList::CreateTrialsFromString(persistent);
     CHECK(ret) << "Invalid --" << switches::kForceFieldTrials <<
@@ skipping 999 matching lines @@
     if (base::win::GetVersion() <= base::win::VERSION_XP)
       uma_name += "_XP";
 
     uma_name += "_PreRead_";
     uma_name += pre_read_percentage;
     AddPreReadHistogramTime(uma_name.c_str(), time);
   }
 #endif
 #endif
 }