More const int definitions for VC++

base/time/time_win.cc

Index: base/time/time_win.cc
diff --git a/base/time/time_win.cc b/base/time/time_win.cc
index bc058040d0c7b5a23923383741bbc811713c6485..2e3dc2e0508ee6736c93d9d9912b2e12e349ffdf 100644
--- a/base/time/time_win.cc
+++ b/base/time/time_win.cc
@@ -131,6 +131,11 @@ uint64 QPCNowRaw() {
 // static
 const int64 Time::kTimeTToMicrosecondsOffset = INT64_C(11644473600000000);
 
+// VS 2015 and above allow these definitions and in this case require them.
+#if _MSC_VER >= 1900
+const int64 base::Time::kQPCOverflowThreshold;
+#endif
+
 // static
 Time Time::Now() {
   if (initial_time == 0)