Make utf8 decoder non-buffered.

sdk/lib/convert/string_conversion.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.convert;
 
 /**
  * This class provides an interface for converters to
  * efficiently transmit String data.
  *
@@ skipping 281 matching lines @@
   }
 }
 
 /**
  * Decodes UTF-8 code units.
  *
  * Forwards the decoded strings to the given [StringConversionSink].
  */
 // TODO(floitsch): make this class public?
 class _Utf8ConversionSink extends ByteConversionSink {
-  static const _MIN_STRING_SIZE = 16;
 
   final _Utf8Decoder _decoder;
   final StringConversionSink _chunkedSink;
   final StringBuffer _buffer;
   _Utf8ConversionSink(StringConversionSink sink, bool allowMalformed)
       : this._(sink, new StringBuffer(), allowMalformed);
 
   _Utf8ConversionSink._(this._chunkedSink, StringBuffer stringBuffer,
                        bool allowMalformed)
       : _decoder = new _Utf8Decoder(stringBuffer, allowMalformed),
         _buffer = stringBuffer;
 
   void close() {
     _decoder.close();
     if (_buffer.isNotEmpty) {
       String accumulated = _buffer.toString();
       _buffer.clear();
       _chunkedSink.addSlice(accumulated, 0, accumulated.length, true);
     } else  {
       _chunkedSink.close();
     }
   }
 
   void add(List<int> chunk) {
     addSlice(chunk, 0, chunk.length, false);
   }
 
-  void addSlice(List<int> chunk, int startIndex, int endIndex,
-                bool isLast) {
+  void addSlice(List<int> chunk, int startIndex, int endIndex, bool isLast) {
     _decoder.convert(chunk, startIndex, endIndex);
-    if (_buffer.length > _MIN_STRING_SIZE) {
+    if (_buffer.isNotEmpty) {
       String accumulated = _buffer.toString();
       _chunkedSink.addSlice(accumulated, 0, accumulated.length, isLast);
       _buffer.clear();
       return;
     }
     if (isLast) close();
   }
 }