Change Duration to take proper named optional parameters.

samples/ui_lib/util/DateUtils.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.
 
 /**
  * General purpose date/time utilities.
  */
 class DateUtils {
   // TODO(jmesserly): localized strings
   static const WEEKDAYS = const ['Monday', 'Tuesday', 'Wednesday', 'Thursday',
@@ skipping 105 matching lines @@
    */
   static String toRecentTimeString(Date then) {
     bool datesAreEqual(Date d1, Date d2) {
       return (d1.year == d2.year) && (d1.month == d2.month) &&
           (d1.day == d2.day);
     }
 
     final now = new Date.now();
     if (datesAreEqual(then, now)) {
       return toHourMinutesString(new Duration(
-          0, then.hour, then.minute, then.second, then.millisecond));
+          days: 0,
+          hours: then.hour,
+          minutes: then.minute,
+          seconds: then.second,
+          milliseconds: then.millisecond));
     }
 
     final today = new Date(now.year, now.month, now.day, 0, 0, 0, 0);
     Duration delta = today.difference(then);
     if (delta.inMilliseconds < Duration.MILLISECONDS_PER_DAY) {
       return YESTERDAY;
     } else if (delta.inMilliseconds < MS_IN_WEEK) {
       return WEEKDAYS[getWeekday(then)];
     } else {
       // TODO(jmesserly): locale specific date format
@@ skipping 36 matching lines @@
     }
     String twoDigits(int n) {
       if (n >= 10) return "${n}";
       return "0${n}";
     }
     String mm =
         twoDigits(duration.inMinutes.remainder(Duration.MINUTES_PER_HOUR));
     return "${hours}:${mm} ${a}";
   }
 }