Let SyncBackupManager keep backup data in memory until shutdown. Only persist

sync/internal_api/sync_rollback_manager.cc

 // Copyright 2014 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 "sync/internal_api/sync_rollback_manager.h"
 
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/read_node.h"
 #include "sync/internal_api/public/read_transaction.h"
 #include "sync/internal_api/public/util/syncer_error.h"
@@ skipping 24 matching lines @@
     const std::string& restored_key_for_bootstrapping,
     const std::string& restored_keystore_key_for_bootstrapping,
     InternalComponentsFactory* internal_components_factory,
     Encryptor* encryptor,
     scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler,
     ReportUnrecoverableErrorFunction report_unrecoverable_error_function,
     CancelationSignal* cancelation_signal) {
   if (SyncRollbackManagerBase::InitInternal(
           database_location,
           internal_components_factory,
+          InternalComponentsFactory::STORAGE_ON_DISK,
           unrecoverable_error_handler.Pass(),
           report_unrecoverable_error_function)) {
     change_delegate_ = change_delegate;
 
     for (size_t i = 0; i < workers.size(); ++i) {
       ModelSafeGroup group = workers[i]->GetModelSafeGroup();
       CHECK(workers_.find(group) == workers_.end());
       workers_[group] = workers[i];
     }
 
@@ skipping 74 matching lines @@
 }
 
 void SyncRollbackManager::NotifyRollbackDone() {
   SyncProtocolError error;
   error.action = ROLLBACK_DONE;
   FOR_EACH_OBSERVER(SyncManager::Observer, *GetObservers(),
                     OnActionableError(error));
 }
 
 }  // namespace syncer