Some non-functional changes: * Use the C++ variant of `BLI_uniquename_cb`. * Use `StringRef` when passing strings as parameters. * Don't pass default name as parameter. Expect name in `unique_node_name` to not be empty.
Some non-functional changes: * Use the C++ variant of `BLI_uniquename_cb`. * Use `StringRef` when passing strings as parameters. * Don't pass default name as parameter. Expect name in `unique_node_name` to not be empty.