Replace admin bar logo

WordPress 3.8 is out I have the following code to remove admin bar logo.

 function no_wp_logo_admin_bar_remove() {
    global $wp_admin_bar;
    $wp_admin_bar->remove_menu('wp-logo');
}
add_action('wp_before_admin_bar_render', 'no_wp_logo_admin_bar_remove', 0);

However I would like to know how can I replace it with my own logo (upload) and not a dashicon?

That’s controlled by a Dashicon (font icon) and a before statement:

#wpadminbar #wp-admin-bar-wp-logo > .ab-item .ab-icon:before {
content: '\f120';
top: 2px;
}

What you’d want is to replace the content call.

Use a built in Dashicon from here: http://melchoyce.github.io/dashicons/

So the smilie would be content: '\f328;`