Move IDBTransactionBackendLevelDB to generic IDBBackingStoreInterface::Transaction Currently it's using IDBBackingStoreLevelDB::Transaction, which hinders the goal of https://bugs.webkit.org/show_bug.cgi?id=123449 - IDBTransactionBackend should be cross platform
Created attachment 215439 [details] Patch v1
http://trac.webkit.org/changeset/158234