Remove usage of dart:json.

samples/third_party/dromaeo/common/BenchUtil.dart

 // Copyright (c) 2011, 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 common;
 
 // Misc benchmark-related utility functions.
 
 class BenchUtil {
   static int get now {
     return new DateTime.now().millisecondsSinceEpoch;
   }
 
   static Map<String, Object> deserialize(String data) {
-    return json.parse(data);
+    return JSON.decode(data);
   }
 
   static String serialize(Object obj) {
-    return json.stringify(obj);
+    return JSON.encode(obj);
   }
 
   // Shuffle a list randomly.
   static void shuffle(List<Object> list) {
     int len = list.length - 1;
     for (int i = 0; i < len; i++) {
       int index = (Math.random() * (len - i)).toInt() + i;
       Object tmp = list[i];
       list[i] = list[index];
       list[index] = tmp;
@@ skipping 45 matching lines @@
     for (Match match in new RegExp(pattern).allMatches(s)) {
       sb.write(s.substring(pos, match.start));
       sb.write(replacement(match));
       pos = match.end;
     }
     sb.write(s.substring(pos));
 
     return sb.toString();
   }
 }