Introduce class Sink<T>.

sdk/lib/convert/json.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;
 
 /**
  * Error thrown by JSON serialization if an object cannot be serialized.
  *
  * The [unsupportedObject] field holds that object that failed to be serialized.
@@ skipping 195 matching lines @@
 
   /**
    * Starts a chunked conversion.
    *
    * The converter works more efficiently if the given [sink] is a
    * [StringConversionSink].
    *
    * Returns a chunked-conversion sink that accepts at most one object. It is
    * an error to invoke `add` more than once on the returned sink.
    */
-  ChunkedConversionSink<Object> startChunkedConversion(
-      ChunkedConversionSink<String> sink) {
+  ChunkedConversionSink<Object> startChunkedConversion(Sink<String> sink) {
     if (sink is! StringConversionSink) {
       sink = new StringConversionSink.from(sink);
     }
     return new _JsonEncoderSink(sink, _toEncodableFunction);
   }
 
   // Override the base-classes bind, to provide a better type.
   Stream<String> bind(Stream<Object> stream) => super.bind(stream);
 }
 
@@ skipping 57 matching lines @@
    * Throws [FormatException] if the input is not valid JSON text.
    */
   dynamic convert(String input) => _parseJson(input, _reviver);
 
   /**
    * Starts a conversion from a chunked JSON string to its corresponding
    * object.
    *
    * The output [sink] receives exactly one decoded element through `add`.
    */
-  StringConversionSink startChunkedConversion(
-      ChunkedConversionSink<Object> sink) {
+  StringConversionSink startChunkedConversion(Sink<Object> sink) {
     return new _JsonDecoderSink(_reviver, sink);
   }
 
   // Override the base-classes bind, to provide a better type.
   Stream<Object> bind(Stream<String> stream) => super.bind(stream);
 }
 
 /**
  * Implements the chunked conversion from a JSON string to its corresponding
  * object.
  *
  * The sink only creates one object, but its input can be chunked.
  */
 // TODO(floitsch): don't accumulate everything before starting to decode.
 class _JsonDecoderSink extends _StringSinkConversionSink {
   final _Reviver _reviver;
-  final ChunkedConversionSink<Object> _chunkedSink;
+  final Sink<Object> _sink;
 
-  _JsonDecoderSink(this._reviver, this._chunkedSink)
+  _JsonDecoderSink(this._reviver, this._sink)
       : super(new StringBuffer());
 
   void close() {
     super.close();
     StringBuffer buffer = _stringSink;
     String accumulated = buffer.toString();
     buffer.clear();
     Object decoded = _parseJson(accumulated, _reviver);
-    _chunkedSink.add(decoded);
-    _chunkedSink.close();
+    _sink.add(decoded);
+    _sink.close();
   }
 }
 
 // Internal optimized JSON parsing implementation.
 external _parseJson(String source, reviver(key, value));
 
 
 // Implementation of encoder/stringifier.
 
 Object _defaultToEncodable(object) => object.toJson();
@@ skipping 165 matching lines @@
         first = false;
       });
       _sink.write('}');
       _seen.remove(object);
       return true;
     } else {
       return false;
     }
   }
 }