WebKit will start using NaN to indicate null/invalid time

base/time.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/time.h"
+
+#include <math.h>
+#if defined(OS_WIN)
+#include <float.h>
+#endif
+
 #include "base/sys_string_conversions.h"
 #include "base/third_party/nspr/prtime.h"
 
 #include "base/logging.h"
 
 namespace base {
 
+namespace {
+#if defined(OS_WIN)
+inline bool isnan(double num) { return !!_isnan(num); }
+#endif
+}
+
 // TimeDelta ------------------------------------------------------------------
 
 int TimeDelta::InDays() const {
   return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);
 }
 
 int TimeDelta::InHours() const {
   return static_cast<int>(delta_ / Time::kMicrosecondsPerHour);
 }
 
@@ skipping 36 matching lines @@
 }
 
 time_t Time::ToTimeT() const {
   if (us_ == 0)
     return 0;  // Preserve 0 so we can tell it doesn't exist.
   return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;
 }
 
 // static
 Time Time::FromDoubleT(double dt) {
-  if (dt == 0)
+  if (dt == 0 || isnan(dt))
     return Time();  // Preserve 0 so we can tell it doesn't exist.
   return Time(static_cast<int64>((dt *
                                   static_cast<double>(kMicrosecondsPerSecond)) +
                                  kTimeTToMicrosecondsOffset));
 }
 
 double Time::ToDoubleT() const {
   if (us_ == 0)
     return 0;  // Preserve 0 so we can tell it doesn't exist.
   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
@@ skipping 45 matching lines @@
   return is_in_range(month, 1, 12) &&
          is_in_range(day_of_week, 0, 6) &&
          is_in_range(day_of_month, 1, 31) &&
          is_in_range(hour, 0, 23) &&
          is_in_range(minute, 0, 59) &&
          is_in_range(second, 0, 60) &&
          is_in_range(millisecond, 0, 999);
 }
 
 }  // namespace base