Fix bad (too specialized) types.

sdk/lib/io/string_transformer.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 const SYSTEM_ENCODING = const SystemEncoding();
 
 /**
  * The system encoding is the current code page on Windows and UTF-8 on
@@ skipping 45 matching lines @@
   // Override the base-class' bind, to provide a better type.
   Stream<List<int>> bind(Stream<String> stream) => super.bind(stream);
 
   external static List<int> _encodeString(String string);
 }
 
 class _WindowsCodePageEncoderSink extends StringConversionSinkBase {
   // TODO(floitsch): provide more efficient conversions when the input is
   // not a String.
 
-  final ByteConversionSink _sink;
+  final ChunkedConversionSink<List<int>> _sink;
 
   _WindowsCodePageEncoderSink(this._sink);
 
   void close() {
     _sink.close();
   }
 
   void add(String string) {
     List<int> encoded = _WindowsCodePageEncoder._encodeString(string);
     if (encoded == null) {
@@ skipping 31 matching lines @@
   // Override the base-class' bind, to provide a better type.
   Stream<String> bind(Stream<List<int>> stream) => super.bind(stream);
 
   external static String _decodeBytes(List<int> bytes);
 }
 
 class _WindowsCodePageDecoderSink extends ByteConversionSinkBase {
   // TODO(floitsch): provide more efficient conversions when the input is
   // a slice.
 
-  final StringConversionSink _sink;
+  final ChunkedConversionSink<String> _sink;
 
   _WindowsCodePageDecoderSink(this._sink);
 
   void close() {
     _sink.close();
   }
 
   void add(List<int> bytes) {
     _sink.add(_WindowsCodePageDecoder._decodeBytes(bytes));
   }
 }