Improve RecentFavorite static function

Signed-off-by: Edward Cheng <c4150221@gmail.com>

Bug fix
Signed-off-by: Edward Cheng <c4150221@gmail.com>

Change var name, make __construct private, init the var at getInstance().
Signed-off-by: Edward Cheng <c4150221@gmail.com>

Fixes.
Signed-off-by: Edward Cheng <c4150221@gmail.com>

streamline code

Signed-off-by: Edward Cheng <c4150221@gmail.com>