Adding Date::ResetCache() API so that the cache values in the Date object...

src/date.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 989 matching lines @@
 function DateToJSON(key) {
   var o = ToObject(this);
   var tv = DefaultNumber(o);
   if (IS_NUMBER(tv) && !$isFinite(tv)) { 
     return null; 
   }
   return o.toISOString();
 }
 
 
+function ResetDateCache() {
+
+  // Reset the local_time_offset:
+  local_time_offset = %DateLocalTimeOffset();
+
+  // Reset the DST offset cache:
+  var cache = DST_offset_cache;
+  cache.offset = 0;
+  cache.start = 0;
+  cache.end = -1;
+  cache.increment = 0;
+  cache.initial_increment = 19 * msPerDay;
+
+  // Reset the timezone cache:
+  timezone_cache_time = $NaN;
+  timezone_cache_timezone = undefined;
+
+  // Reset the ltcache:
+  ltcache.key = null;
+  ltcache.val = null;
+
+  // Reset the ymd_from_time_cache:
+  ymd_from_time_cache = [$NaN, $NaN, $NaN];
+  ymd_from_time_cached_time = $NaN;
+
+  // Reset the date cache:
+  cache = Date_cache;
+  cache.time = $NaN;
+  cache.year = $NaN;
+  cache.string = null;
+}
+
+
 // -------------------------------------------------------------------
 
 function SetupDate() {
   // Setup non-enumerable properties of the Date object itself.
   InstallFunctions($Date, DONT_ENUM, $Array(
     "UTC", DateUTC,
     "parse", DateParse,
     "now", DateNow
   ));
 
@@ skipping 46 matching lines @@
     "toGMTString", DateToGMTString,
     "toUTCString", DateToUTCString,
     "getYear", DateGetYear,
     "setYear", DateSetYear,
     "toISOString", DateToISOString,
     "toJSON", DateToJSON
   ));
 }
 
 SetupDate();