Filter in functions.php: How to know which widget I'm in?

I’m using both widgets, WPP Views and WPP Comments but want my custom HTML filter to differ based on which widget is being used. For example, when viewing popular posts, I want it to display #views. When displaying most comments, I want to display the # comments. What can I use in the php to determine which widget I’m in so I can choose what to display? I set up each widget to flag the correct thing (views has show views on, comments has show comments on) and then used the following code. But stats_views and stats_comments do not appear to be set by the widget… so, is there another way to do it?

function my_custom_popular_posts_html_list( $mostpopular, $instance ){
    $counter = 0;

    $output = '<ul>';  

    foreach( $mostpopular as $popular ) {
             $output .= "<li><div class=\"number\">" . ($counter + 1) . "</div><div class=\"detail\"><a href=\"" . get_the_permalink( $popular->id ) . "\" title=\"" . esc_attr($popular->title) . "\">{$popular->title}</a><div class=\"date\">" . date( 'M j, Y', strtotime($popular->date));
	           if($stats_views == 1) {
    		   		if($popular->pageviews == 1) { $viewStr = 'view'; } else { $viewStr = 'views'; }
	            	$output .= " | {$popular->pageviews} {$viewStr}";
	           }
			   if($stats_comments == 1) {
    			    if($popular->comments == 1) { $cviewStr = 'view'; } else { $cviewStr = 'views'; }
            	    $output .= " | {$popular->comments} {$cviewStr}";
               }
            $output .= "</div></div></li>" . "\n";

        $counter++;
    }

    $output .= '</ul>';

    return $output;
}
add_filter( 'wpp_custom_html', 'my_custom_popular_posts_html_list', 10, 2 );

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