Update type signature of JSON codec.

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 68 matching lines @@
   /**
    * Parses the string and returns the resulting Json object.
    *
    * The optional [reviver] function is called once for each object or list
    * property that has been parsed during decoding. The `key` argument is either
    * the integer list index for a list property, the map string for object
    * properties, or `null` for the final result.
    *
    * The default [reviver] (when not provided) is the identity function.
    */
-  Object decode(String source, {reviver(var key, var value)}) {
+  dynamic decode(String source, {reviver(var key, var value)}) {
     if (reviver == null) return decoder.convert(source);
     return new JsonDecoder(reviver).convert(source);
   }
 
   /**
    * Converts [value] to a JSON string.
    *
    * If value contains objects that are not directly encodable to a JSON
    * string (a value that is not a number, boolean, string, null, list or a map
    * with string keys), the [toEncodable] function is used to convert it to an
    * object that must be directly encodable.
    *
    * If [toEncodable] is omitted, it defaults to calling `.toJson()` on the
    * unencodable object.
    */
-  Object encode(Object value, {toEncodable(var object)}) {
+  String encode(Object value, {toEncodable(var object)}) {
     if (toEncodable == null) return encoder.convert(value);
     return new JsonEncoder(toEncodable).convert(value);
   }
 
   JsonEncoder get encoder => const JsonEncoder();
   JsonDecoder get decoder => const JsonDecoder(null);
 }
 
 typedef _Reviver(var key, var value);
 
 class _ReviverJsonCodec extends JsonCodec {
   final _Reviver _reviver;
   _ReviverJsonCodec(this._reviver);
 
-  Object decode(String source, {reviver(var key, var value)}) {
+  dynamic decode(String source, {reviver(var key, var value)}) {
     if (reviver == null) reviver = _reviver;
     return new JsonDecoder(reviver).convert(source);
   }
 
   JsonDecoder get decoder => new JsonDecoder(_reviver);
 }
 
 /**
  * This class converts JSON objects to strings.
  */
@@ skipping 118 matching lines @@
    * JSON values.
    *
    * If `this` was initialized with a reviver, then the parsing operation
    * invokes the reviver on every object or list property that has been parsed.
    * The arguments are the property name ([String]) or list index ([int]), and
    * the value is the parsed value. The return value of the reviver is used as
    * the value of that property instead the parsed value.
    *
    * Throws [FormatException] if the input is not valid JSON text.
    */
-  Object convert(String input) => _parseJson(input, _reviver);
+  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) {
     return new _JsonDecoderSink(_reviver, sink);
@@ skipping 205 matching lines @@
         first = false;
       });
       sink.write('}');
       seen.remove(object);
       return true;
     } else {
       return false;
     }
   }
 }