Make the package strong-mode clean.

lib/src/percent/decoder.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library convert.percent.decoder;
 
 import 'dart:convert';
 
 import 'package:charcode/ascii.dart';
 import 'package:typed_data/typed_data.dart';
 
 import '../utils.dart';
 
 /// The canonical instance of [PercentDecoder].
 const percentDecoder = const PercentDecoder._();
 
 const _lastPercent = -1;
 
 /// A converter that decodes percent-encoded strings into byte arrays.
 ///
 /// To be maximally flexible, this will decode any percent-encoded byte and
 /// will allow any non-percent-encoded byte other than `%`. By default, it
 /// interprets `+` as `0x2B` rather than `0x20` as emitted by
 /// [Uri.encodeQueryComponent].
 ///
 /// This will throw a [FormatException] if the input string has an incomplete
 /// percent-encoding, or if it contains non-ASCII code units.
-class PercentDecoder extends Converter<String, List<int>> {
+class PercentDecoder
+    extends ChunkedConverter<String, List<int>, String, List<int>> {
   const PercentDecoder._();
 
   List<int> convert(String string) {
     var buffer = new Uint8Buffer();
     var lastDigit = _decode(string.codeUnits, 0, string.length, buffer);
 
     if (lastDigit != null) {
       throw new FormatException(
           "Input ended with incomplete encoded byte.",
           string, string.length);
@@ skipping 196 matching lines @@
 
   for (var i = start; i < end; i++) {
     var codeUnit = codeUnits[i];
     if (codeUnit >= 0 && codeUnit <= 0x7f) continue;
     throw new FormatException(
         "Non-ASCII code unit "
             "U+${codeUnit.toRadixString(16).padLeft(4, '0')}",
         codeUnits, i);
   }
 }