Introduce class Sink<T>.

sdk/lib/convert/html_escape.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;
 
 // TODO(floitsch) - Document - Issue 13097
 const HtmlEscape HTML_ESCAPE = const HtmlEscape();
 
 class HtmlEscapeMode {
@@ skipping 54 matching lines @@
         if (result == null) result = new StringBuffer(text.substring(start, i));
         result.write(replace);
       } else if (result != null) {
         result.write(ch);
       }
     }
 
     return result != null ? result.toString() : null;
   }
 
-  StringConversionSink startChunkedConversion(
-    ChunkedConversionSink<String> sink) {
-
+  StringConversionSink startChunkedConversion(Sink<String> sink) {
     if (sink is! StringConversionSink) {
       sink = new StringConversionSink.from(sink);
     }
     return new _HtmlEscapeSink(this, sink);
   }
 }
 
 class _HtmlEscapeSink extends StringConversionSinkBase {
   final HtmlEscape _escape;
   final StringConversionSink _sink;
 
   _HtmlEscapeSink(this._escape, this._sink);
 
   void addSlice(String chunk, int start, int end, bool isLast) {
     var val = _escape._convert(chunk, start, end);
     if(val == null) {
       _sink.addSlice(chunk, start, end, isLast);
     } else {
       _sink.add(val);
       if (isLast) _sink.close();
     }
   }
 
   void close() => _sink.close();
 }