Make it possible to read a specific number of characters from a string input stream

runtime/bin/file_impl.dart

 // Copyright (c) 2012, 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.
 
 class _FileInputStream extends _BaseDataInputStream implements InputStream {
   _FileInputStream(String name)
       : _data = const [],
         _position = 0,
         _filePosition = 0 {
     var file = new File(name);
@@ skipping 704 matching lines @@
     opened.closeSync();
     return result;
   }
 
   Future<String> readAsText([Encoding encoding = Encoding.UTF_8]) {
     _ensureFileService();
     return readAsBytes().transform((bytes) {
       if (bytes.length == 0) return "";
       var decoder = _StringDecoders.decoder(encoding);
       decoder.write(bytes);
-      return decoder.decoded;
+      return decoder.decoded();
     });
   }
 
   String readAsTextSync([Encoding encoding = Encoding.UTF_8]) {
     var decoder = _StringDecoders.decoder(encoding);
     List<int> bytes = readAsBytesSync();
     if (bytes.length == 0) return "";
     decoder.write(bytes);
-    return decoder.decoded;
+    return decoder.decoded();
   }
 
   List<String> _getDecodedLines(_StringDecoder decoder) {
     List<String> result = [];
     var line = decoder.decodedLine;
     while (line != null) {
       result.add(line);
       line = decoder.decodedLine;
     }
     // If there is more data with no terminating line break we treat
     // it as the last line.
-    var data = decoder.decoded;
+    var data = decoder.decoded();
     if (data != null) {
       result.add(data);
     }
     return result;
   }
 
   Future<List<String>> readAsLines([Encoding encoding = Encoding.UTF_8]) {
     _ensureFileService();
     Completer<List<String>> completer = new Completer<List<String>>();
     return readAsBytes().transform((bytes) {
@@ skipping 408 matching lines @@
           new FileIOException("File closed '$_name'"));
     });
     return completer.future;
   }
 
   final String _name;
   int _id;
 
   SendPort _fileService;
 }