require_once(Mage::getModuleDir('controllers','Mage_CatalogSearch').DS.'ResultController.php');
 abstract class Result extends Mage_CatalogSearch_ResultController
 {
    ...
 }

protected $moduleReader;
public function __construct(
    ...
    MagentoFrameworkModuleDirReader $moduleReader,
    ....
) {
    ....
    $this->moduleReader = $moduleReader;
    ....
}

$this->moduleReader->getModuleDir('Controller', 'Magento_CatalogSearch');

use MagentoFrameworkViewResultPageFactory;

class Test{
    protected $resultPageFactory;
    public function __construct(
            PageFactory $resultPageFactory
        ) {
            $this->resultForwardFactory = $resultForwardFactory;
        }
    public function getanotherClass(){
         $this->resultForwardFactory->getFunctionfromFile();
    }

}