Piwik\ReportRenderer::makeFilenameWithExtension PHP Method

    protected static function makeFilenameWithExtension($filename, $extension)
    {
        // the filename can be used in HTTP headers, remove new lines to prevent HTTP header injection
        $filename = str_replace(array("\n", "\t"), " ", $filename);
        return $filename . "." . $extension;
    }

 public function sendToBrowserInline($filename)
 {
     $filename = ReportRenderer::makeFilenameWithExtension($filename, self::PDF_CONTENT_TYPE);
     $this->TCPDF->Output($filename, 'I');
 }