Pass $atts with edd_downloads_query

One more thing, just need to pass $atts along with the filter

Then I can do this in EDD featured downloads plugin:

Add new "featured" parameter to [downloads] shortcode:
Example usage: [downloads featured="yes"]

    function edd_fd_filter_downloads_shortcode( $out, $pairs, $atts ) {
	    $out['featured'] = '';
        return $out;
    }
    add_filter( 'shortcode_atts_downloads', 'edd_fd_filter_downloads_shortcode', 10, 3 );

Filter the $query to only show the featured downloads

    function edd_fd_filter_downloads_query( $query, $atts ) {
	    if( 'yes' == $atts['featured'] )
		    $query['meta_key'] = 'edd_feature_download';

	    return $query;
    }
    add_filter( 'edd_downloads_query', 'edd_fd_filter_downloads_query', 10, 2 );

How awesome is that :)