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

sync/internal_api/sync_backup_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_backup_manager.h"
 
 #include "sync/internal_api/public/read_node.h"
 #include "sync/internal_api/public/write_transaction.h"
 #include "sync/syncable/directory.h"
 #include "sync/syncable/mutable_entry.h"
@@ skipping 21 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_DEFERRED,
           unrecoverable_error_handler.Pass(),
           report_unrecoverable_error_function)) {
     GetUserShare()->directory->CollectMetaHandleCounts(
         &status_.num_entries_by_type, &status_.num_to_delete_entries_by_type);
 
     HideSyncPreference(PRIORITY_PREFERENCES);
     HideSyncPreference(PREFERENCES);
   }
 }
 
 void SyncBackupManager::SaveChanges() {
-  if (initialized()) {
+  if (initialized())
     NormalizeEntries();
-    GetUserShare()->directory->SaveChanges();
-  }
 }
 
 SyncStatus SyncBackupManager::GetDetailedStatus() const {
   return status_;
 }
 
 ModelTypeSet SyncBackupManager::HandleTransactionEndingChangeEvent(
     const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
     syncable::BaseTransaction* trans) {
   ModelTypeSet types;
@@ skipping 64 matching lines @@
       entry.PutIsUnsynced(false);
 
       // Don't persist on disk so that if backup is aborted before receiving
       // local preference values, values in sync DB are saved.
       GetUserShare()->directory->UnmarkDirtyEntry(
           trans.GetWrappedWriteTrans(), &entry);
     }
   }
 }
 
+void SyncBackupManager::ShutdownOnSyncThread(ShutdownReason reason) {
+  if (reason == SWITCH_MODE_SYNC) {
+    NormalizeEntries();
+    GetUserShare()->directory->SaveChanges();
+  }
+
+  SyncRollbackManagerBase::ShutdownOnSyncThread(reason);
+}
+
 void SyncBackupManager::RegisterDirectoryTypeDebugInfoObserver(
     syncer::TypeDebugInfoObserver* observer) {}
 
 void SyncBackupManager::UnregisterDirectoryTypeDebugInfoObserver(
     syncer::TypeDebugInfoObserver* observer) {}
 
 bool SyncBackupManager::HasDirectoryTypeDebugInfoObserver(
     syncer::TypeDebugInfoObserver* observer) { return false; }
 
 void SyncBackupManager::RequestEmitDebugInfo() {}
 
 }  // namespace syncer