Change IllegalArgumentException to ArgumentError.

runtime/lib/date_patch.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.
 // Dart core library.
 
 // VM implementation of DateImplementation.
 patch class DateImplementation {
   /* patch */ DateImplementation(int year,
                                  [int month = 1,
                                   int day = 1,
                                   int hour = 0,
                                   int minute = 0,
                                   int second = 0,
                                   int millisecond = 0,
                                   bool isUtc = false])
       : this.isUtc = isUtc,
         this.millisecondsSinceEpoch = _brokenDownDateToMillisecondsSinceEpoch(
             year, month, day, hour, minute, second, millisecond, isUtc) {
-    if (millisecondsSinceEpoch === null) throw new IllegalArgumentException();
-    if (isUtc === null) throw new IllegalArgumentException();
+    if (millisecondsSinceEpoch === null) throw new ArgumentError();
+    if (isUtc === null) throw new ArgumentError();
   }
 
   /* patch */ DateImplementation.now()
       : isUtc = false,
         millisecondsSinceEpoch = _getCurrentMs() {
   }
 
   /* patch */ String get timeZoneName {
     if (isUtc) return "UTC";
     return _timeZoneName(millisecondsSinceEpoch);
@@ skipping 284 matching lines @@
 
   static String _timeZoneNameForClampedSeconds(int secondsSinceEpoch)
       native "DateNatives_timeZoneName";
 
   static int _timeZoneOffsetInSecondsForClampedSeconds(int secondsSinceEpoch)
       native "DateNatives_timeZoneOffsetInSeconds";
 
   static int _localTimeZoneAdjustmentInSeconds()
       native "DateNatives_localTimeZoneAdjustmentInSeconds";
 }