diff --git a/dom/time/nsIDOMTimeManager.idl b/dom/time/nsIDOMTimeManager.idl
index 0a026caf1d16..af2f7eceaf46 100644
--- a/dom/time/nsIDOMTimeManager.idl
+++ b/dom/time/nsIDOMTimeManager.idl
@@ -16,5 +16,5 @@ interface nsIDOMMozTimeManager : nsISupports
    * - If |time| is a Date object, |set(time)| is equivalent to 
    *   |set(time.getTime())|.
    */
-  void set(in jsval time);
+  [implicit_jscontext] void set(in jsval time);
 };
diff --git a/hal/Hal.cpp b/hal/Hal.cpp
index d66909d8fa36..bdb58eb1e5e3 100644
--- a/hal/Hal.cpp
+++ b/hal/Hal.cpp
@@ -406,7 +406,39 @@ bool GetLight(LightType light, hal::LightConfiguration* aConfig)
   RETURN_PROXY_IF_SANDBOXED(GetLight(light, aConfig));
 }
 
+static StaticAutoPtr<ObserverList<SystemTimeChange>> sSystemTimeObserver;
 
+static void
+InitializeSystemTimeChangeObserver()
+{
+  if (!sSystemTimeObserver) {
+    sSystemTimeObserver = new ObserverList<SystemTimeChange>;
+    ClearOnShutdown(&sSystemTimeObserver);
+  }
+}
+
+void
+RegisterSystemTimeChangeObserver(SystemTimeObserver *aObserver)
+{
+  AssertMainThread();
+  InitializeSystemTimeChangeObserver();
+  sSystemTimeObserver->AddObserver(aObserver);
+}
+
+void
+UnregisterSystemTimeChangeObserver(SystemTimeObserver *aObserver)
+{
+  AssertMainThread();
+  sSystemTimeObserver->RemoveObserver(aObserver);
+}
+
+void
+NotifySystemTimeChange(const hal::SystemTimeChange& aReason)
+{
+  InitializeSystemTimeChangeObserver();
+  sSystemTimeObserver->Broadcast(aReason);
+}
+ 
 void 
 AdjustSystemClock(int32_t aDeltaMilliseconds)
 {
diff --git a/hal/Hal.h b/hal/Hal.h
index 19f9178be865..afe066f12dda 100644
--- a/hal/Hal.h
+++ b/hal/Hal.h
@@ -50,6 +50,8 @@ class WindowIdentifier;
 extern PRLogModuleInfo *sHalLog;
 #define HAL_LOG(msg) PR_LOG(mozilla::hal::sHalLog, PR_LOG_DEBUG, msg)
 
+typedef Observer<SystemTimeChange> SystemTimeObserver;
+
 } // namespace hal
 
 namespace MOZ_HAL_NAMESPACE {
@@ -255,6 +257,24 @@ void SetTimezone(const nsCString& aTimezoneSpec);
  */
 nsCString GetTimezone();
 
+/**
+ * Register observer for system time changed notification.
+ * @param aObserver The observer that should be added.
+ */
+void RegisterSystemTimeChangeObserver(hal::SystemTimeObserver* aObserver);
+
+/**
+ * Unregister the observer for system time changed.
+ * @param aObserver The observer that should be removed.
+ */
+void UnregisterSystemTimeChangeObserver(hal::SystemTimeObserver* aObserver);
+
+/**
+ * Notify of a change in the system cloeck or time zone.
+ * @param aReason
+ */
+void NotifySystemTimeChange(const hal::SystemTimeChange& aReason);
+
 /**
  * Reboot the device.
  */
diff --git a/hal/HalTypes.h b/hal/HalTypes.h
index 65b0b85a93b1..e93147e02c6d 100644
--- a/hal/HalTypes.h
+++ b/hal/HalTypes.h
@@ -74,6 +74,13 @@ enum WakeLockControl {
   NUM_WAKE_LOCK
 };
 
+enum SystemTimeChange {
+  SYS_TIME_CHANGE_UNKNOWN = -1,
+  SYS_TIME_CHANGE_CLOCK,
+  SYS_TIME_CHANGE_TZ,
+  SYS_TIME_CHANGE_GUARD
+};
+
 } // namespace hal
 } // namespace mozilla
 
@@ -146,7 +153,16 @@ struct ParamTraits<mozilla::hal::ProcessPriority>:
                         mozilla::hal::NUM_PROCESS_PRIORITY> {
 };
 
-
+/**
+ * SystemTimeChange serializer.
+ */
+template <>
+struct ParamTraits<mozilla::hal::SystemTimeChange>
+  : public EnumSerializer<mozilla::hal::SystemTimeChange,
+                          mozilla::hal::SYS_TIME_CHANGE_UNKNOWN,
+                          mozilla::hal::SYS_TIME_CHANGE_GUARD>
+{};
+ 
 } // namespace IPC
 
 #endif // mozilla_hal_Types_h
diff --git a/hal/gonk/GonkHal.cpp b/hal/gonk/GonkHal.cpp
index 228d99249cbf..ea5ed339d785 100644
--- a/hal/gonk/GonkHal.cpp
+++ b/hal/gonk/GonkHal.cpp
@@ -581,6 +581,10 @@ sys_clock_settime(clockid_t clk_id, const struct timespec *tp)
 void 
 AdjustSystemClock(int32_t aDeltaMilliseconds)
 {
+  if (aDeltaMilliseconds == 0) {
+    return;
+  }
+  
   struct timespec now;
   
   // Preventing context switch before setting system clock 
@@ -600,16 +604,26 @@ AdjustSystemClock(int32_t aDeltaMilliseconds)
     now.tv_sec -= 1;  
   }
   // we need to have root privilege. 
-  sys_clock_settime(CLOCK_REALTIME, &now);   
+  if (sys_clock_settime(CLOCK_REALTIME, &now) != 0) {
+    NS_ERROR("sys_clock_settime failed");
+    return;
+  }
+  
+  hal::NotifySystemTimeChange(hal::SYS_TIME_CHANGE_CLOCK);
 }
 
 void 
 SetTimezone(const nsCString& aTimezoneSpec)
-{ 
+{
+  if (aTimezoneSpec.Equals(GetTimezone())) {
+    return;
+  }
+
   property_set("persist.sys.timezone", aTimezoneSpec.get());
   // this function is automatically called by the other time conversion 
   // functions that depend on the timezone. To be safe, we call it manually.  
   tzset();
+  hal::NotifySystemTimeChange(hal::SYS_TIME_CHANGE_TZ);
 }
 
 nsCString 
diff --git a/hal/sandbox/PHal.ipdl b/hal/sandbox/PHal.ipdl
index f8124936eb16..5b6fb70e1d2a 100644
--- a/hal/sandbox/PHal.ipdl
+++ b/hal/sandbox/PHal.ipdl
@@ -24,6 +24,7 @@ using mozilla::hal::SwitchDevice;
 using mozilla::hal::ProcessPriority;
 using nsIntRect;
 using PRTime;
+using mozilla::hal::SystemTimeChange;
 
 namespace mozilla {
 
@@ -86,6 +87,7 @@ child:
     NotifyWakeLockChange(WakeLockInformation aWakeLockInfo);
     NotifyScreenConfigurationChange(ScreenConfiguration aScreenOrientation);
     NotifySwitchChange(SwitchEvent aEvent);
+    NotifySystemTimeChange(SystemTimeChange aReason); 
 
 parent:
     Vibrate(uint32_t[] pattern, uint64_t[] id, PBrowser browser);
diff --git a/hal/sandbox/SandboxHal.cpp b/hal/sandbox/SandboxHal.cpp
index 0dd97f392799..0e8c97f67810 100644
--- a/hal/sandbox/SandboxHal.cpp
+++ b/hal/sandbox/SandboxHal.cpp
@@ -676,6 +676,11 @@ public:
     hal::SetProcessPriority(aPid, aPriority);
     return true;
   }
+
+  void Notify(const SystemTimeChange& aReason)
+  {
+    unused << SendNotifySystemTimeChange(aReason);
+  }
 };
 
 class HalChild : public PHalChild {
@@ -712,6 +717,12 @@ public:
     hal::NotifySwitchChange(aEvent);
     return true;
   }
+
+  virtual bool
+  RecvNotifySystemTimeChange(const SystemTimeChange& aReason) {
+    hal::NotifySystemTimeChange(aReason);
+    return true;
+  }
 };
 
 bool