browser.php
protected function fetch($url, $encoding, $depth = 0)
    {
        $http_referer = $this->history->getUrl();        
        if ($http_referer) {
            $this->user_agent->setReferer($http_referer->asString());
        } else {
            $this->user_agent->setReferer(null);
        }

        $response = $this->user_agent->fetchResponse($url, $encoding);
        if ($response->isError()) {
            return new SimplePage($response);
        }

        return $this->parse($response, $depth);
    }
protected function fetch($url, $encoding, $depth = 0)
    {
        $http_referer = $this->history->getUrl();        
        if ($http_referer) {
            $this->user_agent->setReferer($http_referer->asString());
        } else {
            $this->user_agent->setReferer(null);
        }

        $response = $this->user_agent->fetchResponse($url, $encoding);
        if ($response->isError()) {
            return new SimplePage($response);
        }

        return $this->parse($response, $depth);
    }
Fetches a page.
Jointly recursive with the parse() method as it descends a frameset.

@param string/SimpleUrl $url      Target to fetch.
@param SimpleEncoding $encoding   GET/POST parameters.
@param int $depth                 Nested frameset depth protection.

@return SimplePage                Parsed page.