diff -r 000000000000 -r 6474c204b198 dom/time/DateCacheCleaner.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/time/DateCacheCleaner.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DateCacheCleaner.h"
+
+#include "jsapi.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Hal.h"
+#include "mozilla/StaticPtr.h"
+#include "nsCxPusher.h"
+
+using namespace mozilla::hal;
+
+namespace mozilla {
+namespace dom {
+namespace time {
+
+class DateCacheCleaner : public SystemTimezoneChangeObserver
+{
+public:
+  DateCacheCleaner()
+  {
+    RegisterSystemTimezoneChangeObserver(this);
+  }
+
+  ~DateCacheCleaner()
+  {
+    UnregisterSystemTimezoneChangeObserver(this);
+  }
+  void Notify(const SystemTimezoneChangeInformation& aSystemTimezoneChangeInfo)
+  {
+    mozilla::AutoSafeJSContext cx;
+    JS_ClearDateCaches(cx);
+  }
+
+};
+
+StaticAutoPtr<DateCacheCleaner> sDateCacheCleaner;
+
+void
+InitializeDateCacheCleaner()
+{
+  if (!sDateCacheCleaner) {
+    sDateCacheCleaner = new DateCacheCleaner();
+    ClearOnShutdown(&sDateCacheCleaner);
+  }
+}
+
+} // namespace time
+} // namespace dom
+} // namespace mozilla