diff -aruN nspr-4.8.6/mozilla/nsprpub/pr/include/prtime.h nspr-4.8.6.N/mozilla/nsprpub/pr/include/prtime.h
--- nspr-4.8.6/mozilla/nsprpub/pr/include/prtime.h	2009-03-03 08:17:48.000000000 -0800
+++ nspr-4.8.6.N/mozilla/nsprpub/pr/include/prtime.h	2015-04-29 16:32:24.000000000 -0700
@@ -206,7 +206,10 @@
  *     should treat them as "read-only".
  */
 
-NSPR_API(void) PR_NormalizeTime(
+NSPR_API(PRTime) PR_NormalizeTime(
+    PRExplodedTime *exploded, PRTimeParamFn params);
+
+NSPR_API(void) PR_NormalizeTime_NoDSTAdjust(
     PRExplodedTime *exploded, PRTimeParamFn params);
 
 /**********************************************************************/
diff -aruN nspr-4.8.6/mozilla/nsprpub/pr/src/misc/prtime.c nspr-4.8.6.N/mozilla/nsprpub/pr/src/misc/prtime.c
--- nspr-4.8.6/mozilla/nsprpub/pr/src/misc/prtime.c	2015-04-29 16:33:57.000000000 -0700
+++ nspr-4.8.6.N/mozilla/nsprpub/pr/src/misc/prtime.c	2015-04-29 16:33:10.000000000 -0700
@@ -272,7 +272,7 @@
 
     /* Normalize first.  Do this on our copy */
     copy = *exploded;
-    PR_NormalizeTime(&copy, PR_GMTParameters);
+    PR_NormalizeTime_NoDSTAdjust(&copy, PR_GMTParameters);
 
     numDays = DAYS_BETWEEN_YEARS(1970, copy.tm_year);
     
@@ -387,9 +387,29 @@
     }
 }
 
-PR_IMPLEMENT(void)
+NSPR_API(PRTime)
 PR_NormalizeTime(PRExplodedTime *time, PRTimeParamFn params)
 {
+    PRTime resolvedtime;
+    PR_NormalizeTime_NoDSTAdjust(time, PR_LocalTimeParameters);
+
+    // Resolve DST shifts explicitly. Note that this will also update *time
+    // with the corrected time.
+    resolvedtime = PR_ImplodeTime(time);
+    PR_ExplodeTime(resolvedtime, params, time);
+
+    // Return the DST-resolved PRTime.
+    return resolvedtime;
+}
+
+// This function normalizes time, but does not always resolve Daylight Savings
+// Time correctly (see SAPPHIRE-10133 for an example). It is the original
+// built-in PR_NormalizeTime function in NSPR, but should not be used outside
+// of the functions in this file - users should continue to utilize the newer
+// PR_NormalizeTime function below (see SAPPHIRE-10152).
+PR_IMPLEMENT(void)
+PR_NormalizeTime_NoDSTAdjust(PRExplodedTime *time, PRTimeParamFn params)
+{
     int daysInMonth;
     PRInt32 numDays;
 
@@ -1723,7 +1743,7 @@
    * Mainly to compute wday and yday, but normalized time is also required
    * by the check below that works around a Visual C++ 2005 mktime problem.
    */
-  PR_NormalizeTime(result, PR_GMTParameters);
+  PR_NormalizeTime_NoDSTAdjust(result, PR_GMTParameters);
   /* The remaining work is to set the gmt and dst offsets in tm_params. */
 
   if (zone == TT_UNKNOWN && default_to_gmt)