Invalidate OS-specific datetime cache on configuration change notification

src/platform-win32.cc

Index: src/platform-win32.cc
===================================================================
--- src/platform-win32.cc	(revision 19774)
+++ src/platform-win32.cc	(working copy)
@@ -251,6 +251,8 @@
   // timestamp taking into account daylight saving.
   char* LocalTimezone();
 
+  static void TimeZoneChanged() { tz_initialized_ = false; }
+
  private:
   // Constants for time conversion.
   static const int64_t kTimeEpoc = 116444736000000000LL;
@@ -611,6 +613,11 @@
 }
 
 
+void OS::TimeZoneChanged() {
+  Win32Time::TimeZoneChanged();
+}
+
+
 int OS::GetLastError() {
   return ::GetLastError();
 }