kill on longpress back

packages/apps/Settings/src/com/android/settings/DevelopmentSettings.java:495: cannot find symbol
symbol  : variable KILL_APP_LONGPRESS_BACK
location: class android.provider.Settings.Secure
                Settings.Secure.KILL_APP_LONGPRESS_BACK,
                               ^
packages/apps/Settings/src/com/android/settings/DevelopmentSettings.java:501: cannot find symbol
symbol  : variable KILL_APP_LONGPRESS_BACK
location: class android.provider.Settings.Secure
            getActivity().getContentResolver(), Settings.Secure.KILL_APP_LONGPRESS_BACK, 0) != 0);
                                                               ^