Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/metrics/variations/variations_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.
 
 #include "chrome/browser/metrics/variations/variations_service.h"
 
 #include <set>
 
 #include "base/base64.h"
 #include "base/build_time.h"
@@ skipping 142 matching lines @@
 
   // Perform the first fetch.
   FetchVariationsSeed();
 
   // Repeat this periodically.
   timer_.Start(FROM_HERE, base::TimeDelta::FromHours(kSeedFetchPeriodHours),
                this, &VariationsService::FetchVariationsSeed);
 }
 
 // static
-void VariationsService::RegisterPrefs(PrefService* prefs) {
+void VariationsService::RegisterPrefs(PrefServiceSimple* prefs) {
   prefs->RegisterStringPref(prefs::kVariationsSeed, std::string());
   prefs->RegisterInt64Pref(prefs::kVariationsSeedDate,
                            base::Time().ToInternalValue());
 }
 
 void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) {
   create_trials_from_seed_called_ = called;
 }
 
 void VariationsService::DoActualFetch() {
@@ skipping 337 matching lines @@
                                       variation_id);
     }
   }
 
   trial->SetForced();
   if (IsStudyExpired(study, reference_date))
     trial->Disable();
 }
 
 }  // namespace chrome_variations