public Parameters parseParametersWithLegacyFallback(
      ProtoParametersSerialization protoParametersSerialization) throws GeneralSecurityException {
    if (!hasParserForParameters(protoParametersSerialization)) {
      return new LegacyProtoParameters(protoParametersSerialization);
    } else {
      return parseParameters(protoParametersSerialization);
    }
  }
Returns a Parameters object from a protoKeySerialization, even if no parser has been
registered.

<p>Falling back is useful because we need to have a parameters object even if no parser is
registered (e.g. for when we create a Key from a key template/parameters name object).
java_src/src/main/java/com/google/crypto/tink/internal/MutableSerializationRegistry.java