The MetricsService are not initialized unless the user have opted in...

chrome/browser/metrics/metrics_service.cc

 // Copyright (c) 2006-2008 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
@@ skipping 405 matching lines @@
   SetRecording(false);
 }
 
 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);
+      client_id_ = WideToUTF8(pref->GetString(prefs::kMetricsClientID));
+      if (client_id_.empty()) {
+        client_id_ = GenerateClientID();
+        pref->SetString(prefs::kMetricsClientID, UTF8ToWide(client_id_));
+
+        // Might as well make a note of how long this ID has existed
+        pref->SetString(prefs::kMetricsClientIDTimestamp,
+                        Int64ToWString(Time::Now().ToTimeT()));
+      }
+    }
     StartRecording();
     ListenerRegistration(true);
   } else {
     // Turn off all observers.
     ListenerRegistration(false);
     PushPendingLogsToUnsentLists();
     DCHECK(!pending_log());
     if (state_ > INITIAL_LOG_READY && unsent_logs())
       state_ = SEND_OLD_INITIAL_LOGS;
   }
@@ skipping 142 matching lines @@
 
   if (WideToUTF8(pref->GetString(prefs::kStabilityStatsVersion)) !=
       MetricsLog::GetVersionString()) {
     // This is a new version, so we don't want to confuse the stats about the
     // old version with info that we upload.
     DiscardOldStabilityStats(pref);
     pref->SetString(prefs::kStabilityStatsVersion,
                     UTF8ToWide(MetricsLog::GetVersionString()));
   }
 
-  client_id_ = WideToUTF8(pref->GetString(prefs::kMetricsClientID));
-  if (client_id_.empty()) {
-    client_id_ = GenerateClientID();
-    pref->SetString(prefs::kMetricsClientID, UTF8ToWide(client_id_));
-
-    // Might as well make a note of how long this ID has existed
-    pref->SetString(prefs::kMetricsClientIDTimestamp,
-                    Int64ToWString(Time::Now().ToTimeT()));
-  }
-
   // Update session ID
   session_id_ = pref->GetInteger(prefs::kMetricsSessionID);
   ++session_id_;
   pref->SetInteger(prefs::kMetricsSessionID, session_id_);
 
   // Stability bookkeeping
   IncrementPrefValue(prefs::kStabilityLaunchCount);
 
   if (!pref->GetBoolean(prefs::kStabilityExitedCleanly)) {
     IncrementPrefValue(prefs::kStabilityCrashCount);
@@ skipping 1228 matching lines @@
       L"." + key;
   prof_prefs->SetInteger(pref_key.c_str(), value);
 }
 
 static bool IsSingleThreaded() {
   static PlatformThreadId thread_id = 0;
   if (!thread_id)
     thread_id = PlatformThread::CurrentId();
   return PlatformThread::CurrentId() == thread_id;
 }