Add one-time randomization support for FieldTrial, and the ability to

chrome/browser/metrics/metrics_service.cc

 // Copyright (c) 2011 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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It
@@ skipping 453 matching lines @@
   SetRecording(true);
   SetReporting(false);
 }
 
 void MetricsService::Stop() {
   HandleIdleSinceLastTransmission(false);
   SetReporting(false);
   SetRecording(false);
 }
 
+std::string MetricsService::GetClientId() {
+  return client_id_;
+}
+
 void MetricsService::SetRecording(bool enabled) {
   DCHECK(IsSingleThreaded());
 
   if (enabled == recording_active_)
     return;
 
   if (enabled) {
     if (client_id_.empty()) {
       PrefService* pref = g_browser_process->local_state();
       DCHECK(pref);
@@ skipping 1201 matching lines @@
     thread_id = base::PlatformThread::CurrentId();
   return base::PlatformThread::CurrentId() == thread_id;
 }
 
 #if defined(OS_CHROMEOS)
 void MetricsService::StartExternalMetrics() {
   external_metrics_ = new chromeos::ExternalMetrics;
   external_metrics_->Start();
 }
 #endif