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

sync/internal_api/sync_manager_impl.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 "sync/internal_api/sync_manager_impl.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/bind.h"
@@ skipping 326 matching lines @@
       args->restored_keystore_key_for_bootstrapping));
   sync_encryption_handler_->AddObserver(this);
   sync_encryption_handler_->AddObserver(&debug_info_event_listener_);
   sync_encryption_handler_->AddObserver(&js_sync_encryption_handler_observer_);
 
   base::FilePath absolute_db_path = database_path_;
   DCHECK(absolute_db_path.IsAbsolute());
 
   scoped_ptr<syncable::DirectoryBackingStore> backing_store =
       args->internal_components_factory->BuildDirectoryBackingStore(
-                                             args->credentials.email,
-                                             absolute_db_path).Pass();
+          InternalComponentsFactory::STORAGE_ON_DISK,
+          args->credentials.email, absolute_db_path).Pass();
 
   DCHECK(backing_store.get());
   share_.directory.reset(
       new syncable::Directory(
           backing_store.release(),
           unrecoverable_error_handler_.get(),
           report_unrecoverable_error_function_,
           sync_encryption_handler_.get(),
           sync_encryption_handler_->GetCryptographerUnsafe()));
   share_.sync_credentials = args->credentials;
@@ skipping 780 matching lines @@
 int SyncManagerImpl::GetDefaultNudgeDelay() {
   return kDefaultNudgeDelayMilliseconds;
 }
 
 // static.
 int SyncManagerImpl::GetPreferencesNudgeDelay() {
   return kPreferencesNudgeDelayMilliseconds;
 }
 
 }  // namespace syncer