[Intl] Cleanup some code

pkg/intl/lib/date_symbol_data_file.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.
 
 /**
  * This file should be imported, along with date_format.dart in order to read
  * locale data from files in the file system.
  */
 
 library date_symbol_data_json;
@@ skipping 22 matching lines @@
       reader2, (x) => x, availableLocalesForDateFormatting));
   return initializeIndividualLocaleDateFormatting(
       (symbols, patterns) {
         return Future.wait([
             symbols.initLocale(locale),
             patterns.initLocale(locale)]);
       });
 }
 
 /** Defines how new date symbol entries are created. */
-DateSymbols _createDateSymbol(Map map) {
-  return new DateSymbols.deserializeFromMap(map);
-}
+DateSymbols _createDateSymbol(Map map) =>
+    new DateSymbols.deserializeFromMap(map);