Merge fixes for issue 736 and 764 to 2.1 branch for Chrome 5.

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 320 matching lines @@
 
 // Compute number of days given a year, month, date.
 // Note that month and date can lie outside the normal range.
 //   For example:
 //     MakeDay(2007, -4, 20) --> MakeDay(2006, 8, 20)
 //     MakeDay(2007, -33, 1) --> MakeDay(2004, 3, 1)
 //     MakeDay(2007, 14, -50) --> MakeDay(2007, 8, 11)
 function MakeDay(year, month, date) {
   if (!$isFinite(year) || !$isFinite(month) || !$isFinite(date)) return $NaN;
 
-  year = TO_INTEGER(year);
-  month = TO_INTEGER(month);
-  date = TO_INTEGER(date);
+  // Convert to integer and map -0 to 0.
+  year = TO_INTEGER_MAP_MINUS_ZERO(year);
+  month = TO_INTEGER_MAP_MINUS_ZERO(month);
+  date = TO_INTEGER_MAP_MINUS_ZERO(date);
 
   if (year < kMinYear || year > kMaxYear ||
       month < kMinMonth || month > kMaxMonth ||
       date < kMinDate || date > kMaxDate) {
     return $NaN;
   }
 
   // Now we rely on year, month and date being SMIs.
   return %DateMakeDay(year, month, date);
 }
@@ skipping 750 matching lines @@
     "toGMTString", DateToGMTString,
     "toUTCString", DateToUTCString,
     "getYear", DateGetYear,
     "setYear", DateSetYear,
     "toISOString", DateToISOString,
     "toJSON", DateToJSON
   ));
 }
 
 SetupDate();