Remove usage of dart:json.

pkg/intl/tool/generate_locale_data_files.dart

 // Copyright (c) 2012, 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.
 
 /**
  * A utility program to take locale data represented as a Dart map whose keys
  * are locale names and write it into individual JSON files named by locale.
  * This should be run any time the locale data changes.
  *
  * The files are written under "data/dates", in two subdirectories, "symbols"
  * and "patterns". In "data/dates" it will also generate "localeList.dart",
  * which is sourced by the date_symbol_data... files.
  */
 
 import '../lib/date_symbol_data_local.dart';
 import '../lib/date_time_patterns.dart';
 import '../lib/intl.dart';
+import 'dart:convert';
 import 'dart:io';
-import 'dart:json' as json;
 import '../test/data_directory.dart';
 import 'package:path/path.dart' as path;
 
 main() {
   initializeDateFormatting("en_IGNORED", null);
   writeSymbolData();
   writePatternData();
   writeLocaleList();
 }
 
@@ skipping 33 matching lines @@
 void writeSymbols(locale, symbols) {
   var file = new File(path.join(dataDirectory, 'symbols', '${locale}.json'));
   var output = file.openWrite();
   writeToJSON(symbols, output);
   output.close();
 }
 
 void writePatterns(locale, patterns) {
   var file = new File(path.join(dataDirectory, 'patterns', '${locale}.json'));
   var output = file.openWrite();
-  output.write(json.stringify(patterns));
+  output.write(JSON.encode(patterns));
   output.close();
 }
 
 void writeToJSON(dynamic data, IOSink out) {
-  out.write(json.stringify(data.serializeToMap()));
+  out.write(JSON.encode(data.serializeToMap()));
 }