Add enable-sync-directory-operation to about:flags

webkit/fileapi/syncable/syncable_file_system_util.cc

Index: webkit/fileapi/syncable/syncable_file_system_util.cc
diff --git a/webkit/fileapi/syncable/syncable_file_system_util.cc b/webkit/fileapi/syncable/syncable_file_system_util.cc
index e785ba46d4d91002261c0a231998c99dc051b4da..3dd28f4af9866765e491a70e18a1b3c3ae5f8031 100644
--- a/webkit/fileapi/syncable/syncable_file_system_util.cc
+++ b/webkit/fileapi/syncable/syncable_file_system_util.cc
@@ -29,6 +29,10 @@ bool is_directory_operation_enabled = false;
 
 }
 
+const char* GetFlagForSyncFileSystemDirectoryOperation() {
+  return kEnableSyncDirectoryOperation;
+}
+
 bool RegisterSyncableFileSystem(const std::string& service_name) {
   return ExternalMountPoints::GetSystemInstance()->RegisterFileSystem(
       service_name, fileapi::kFileSystemTypeSyncable, base::FilePath());