Remove the drive status from the ash try.

ash/system/tray/system_tray_notifier.cc

Index: ash/system/tray/system_tray_notifier.cc
diff --git a/ash/system/tray/system_tray_notifier.cc b/ash/system/tray/system_tray_notifier.cc
index 5801ce6b5b9c4c82dda0c0a3faf5f856717b42d1..1a55f8a1af8731457174bcf5eebbee9922eaba81 100644
--- a/ash/system/tray/system_tray_notifier.cc
+++ b/ash/system/tray/system_tray_notifier.cc
@@ -53,14 +53,6 @@ void SystemTrayNotifier::RemoveClockObserver(ClockObserver* observer) {
   clock_observers_.RemoveObserver(observer);
 }
 
-void SystemTrayNotifier::AddDriveObserver(DriveObserver* observer) {
-  drive_observers_.AddObserver(observer);
-}
-
-void SystemTrayNotifier::RemoveDriveObserver(DriveObserver* observer) {
-  drive_observers_.RemoveObserver(observer);
-}
-
 void SystemTrayNotifier::AddIMEObserver(IMEObserver* observer) {
   ime_observers_.AddObserver(observer);
 }
@@ -276,13 +268,6 @@ void SystemTrayNotifier::NotifySystemClockCanSetTimeChanged(bool can_set_time) {
                     OnSystemClockCanSetTimeChanged(can_set_time));
 }
 
-void SystemTrayNotifier::NotifyDriveJobUpdated(
-    const DriveOperationStatus& status) {
-  FOR_EACH_OBSERVER(DriveObserver,
-                    drive_observers_,
-                    OnDriveJobUpdated(status));
-}
-
 void SystemTrayNotifier::NotifyRefreshIME() {
   FOR_EACH_OBSERVER(IMEObserver,
                     ime_observers_,