public function save(Tracker_Permission_PermissionRequest $request, Tracker_Permission_PermissionSetter $permission_setter)
 {
     $tracker = $permission_setter->getTracker();
     if ($this->checkPermissionValidity($request, $tracker)) {
         $this->getChainOfResponsability()->apply($request, $permission_setter);
         EventManager::instance()->processEvent(TRACKER_EVENT_TRACKER_PERMISSIONS_CHANGE, array('tracker' => $tracker));
     }
 }