[Sync] Remove backend unrecoverable error handler

sync/internal_api/sync_rollback_manager_base.cc

Index: sync/internal_api/sync_rollback_manager_base.cc
diff --git a/sync/internal_api/sync_rollback_manager_base.cc b/sync/internal_api/sync_rollback_manager_base.cc
index 55d2e8d36f50b441dcb409f9ce761d833e2e068d..ab2d97e72606c24f0828d75c2f6c7024bb8b889a 100644
--- a/sync/internal_api/sync_rollback_manager_base.cc
+++ b/sync/internal_api/sync_rollback_manager_base.cc
@@ -49,9 +49,9 @@ bool SyncRollbackManagerBase::InitInternal(
     const base::FilePath& database_location,
     InternalComponentsFactory* internal_components_factory,
     InternalComponentsFactory::StorageOption storage,
-    scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler,
+    const WeakHandle<UnrecoverableErrorHandler>& unrecoverable_error_handler,
     const base::Closure& report_unrecoverable_error_function) {
-  unrecoverable_error_handler_ = unrecoverable_error_handler.Pass();
+  unrecoverable_error_handler_ = unrecoverable_error_handler;
   report_unrecoverable_error_function_ = report_unrecoverable_error_function;
 
   if (!InitBackupDB(database_location, internal_components_factory, storage)) {
@@ -245,7 +245,7 @@ bool SyncRollbackManagerBase::InitBackupDB(
   share_.directory.reset(
       new syncable::Directory(
           backing_store.release(),
-          unrecoverable_error_handler_.get(),
+          unrecoverable_error_handler_,
           report_unrecoverable_error_function_,
           NULL,
           NULL));