WebKit will start using NaN to indicate null/invalid time

base/time.cc

Index: base/time.cc
diff --git a/base/time.cc b/base/time.cc
index 859810e7cfe36b8f894a638803ef2b7a315ae086..bb171c261d9cd12bd574d9807f3e39eb8dfc7756 100644
--- a/base/time.cc
+++ b/base/time.cc
@@ -3,6 +3,12 @@
 // 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"
 
@@ -10,6 +16,12 @@
 
 namespace base {
 
+namespace {
+#if defined(OS_WIN)
+inline bool isnan(double num) { return !!_isnan(num); }
+#endif
+}
+
 // TimeDelta ------------------------------------------------------------------
 
 int TimeDelta::InDays() const {
@@ -66,7 +78,7 @@ time_t Time::ToTimeT() const {
 
 // 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)) +