Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/metrics/metrics_service.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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It
@@ skipping 418 matching lines @@
   }
 
  private:
   ~MetricsMemoryDetails() {}
 
   base::Closure callback_;
   DISALLOW_COPY_AND_ASSIGN(MetricsMemoryDetails);
 };
 
 // static
-void MetricsService::RegisterPrefs(PrefService* local_state) {
+void MetricsService::RegisterPrefs(PrefServiceSimple* local_state) {
   DCHECK(IsSingleThreaded());
   local_state->RegisterStringPref(prefs::kMetricsClientID, "");
   local_state->RegisterIntegerPref(prefs::kMetricsLowEntropySource,
                                    kLowEntropySourceNotSet);
   local_state->RegisterInt64Pref(prefs::kMetricsClientIDTimestamp, 0);
   local_state->RegisterInt64Pref(prefs::kStabilityLaunchTimeSec, 0);
   local_state->RegisterInt64Pref(prefs::kStabilityLastTimestampSec, 0);
   local_state->RegisterStringPref(prefs::kStabilityStatsVersion, "");
   local_state->RegisterInt64Pref(prefs::kStabilityStatsBuildTime, 0);
   local_state->RegisterBooleanPref(prefs::kStabilityExitedCleanly, true);
@@ skipping 1542 matching lines @@
   if (local_state) {
     const PrefService::Preference* uma_pref =
         local_state->FindPreference(prefs::kMetricsReportingEnabled);
     if (uma_pref) {
       bool success = uma_pref->GetValue()->GetAsBoolean(&result);
       DCHECK(success);
     }
   }
   return result;
 }