Make ~/, round, ceil, floor, truncate return ints. Remove toInt.

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 _DateImpl.
 patch class _DateImpl {
   /* patch */ _DateImpl(int year,
                         int month,
                         int day,
@@ skipping 165 matching lines @@
         ((y.remainder(100) != 0) || (y.remainder(400) == 0));
   }
 
   static _brokenDownDateToMillisecondsSinceEpoch(
       int year, int month, int day,
       int hour, int minute, int second, int millisecond,
       bool isUtc) {
     // Simplify calculations by working with zero-based month.
     --month;
     // Deal with under and overflow.
-    year += (month / 12).floor().toInt();
+    year += (month / 12).floor();
     month = month % 12;
 
     // First compute the seconds in UTC, independent of the [isUtc] flag. If
     // necessary we will add the time-zone offset later on.
     int days = day - 1;
     days += _DAYS_UNTIL_MONTH[_isLeapYear(year) ? 1 : 0][month];
     days += _dayFromYear(year);
     int millisecondsSinceEpoch = days * Duration.MILLISECONDS_PER_DAY +
         hour * Duration.MILLISECONDS_PER_HOUR +
         minute * Duration.MILLISECONDS_PER_MINUTE+
@@ skipping 118 matching lines @@
 
   static String _timeZoneNameForClampedSeconds(int secondsSinceEpoch)
       native "DateNatives_timeZoneName";
 
   static int _timeZoneOffsetInSecondsForClampedSeconds(int secondsSinceEpoch)
       native "DateNatives_timeZoneOffsetInSeconds";
 
   static int _localTimeZoneAdjustmentInSeconds()
       native "DateNatives_localTimeZoneAdjustmentInSeconds";
 }