Add styles for TinyMCE editor

// tinymce styles
// Callback function to insert 'styleselect' into the $buttons array
function my_mce_buttons_2( $buttons ) {
	array_unshift( $buttons, 'styleselect' );
	return $buttons;
}
// Register our callback to the appropriate filter
add_filter( 'mce_buttons_2', 'my_mce_buttons_2' );

// Callback function to filter the MCE settings
function my_mce_before_init_insert_formats( $init_array ) {
	// Define the style_formats array
	$style_formats = array(
		// Each array child is a format with it's own settings
		array(
			'title' => 'Button',
			'classes' => 'btn',
			'selector' => 'a',
			'wrapper' => false,
		),
        array(
			'title' => 'Info box',
			'block' => 'div',
			'classes' => 'info-box',
			'wrapper' => true,
		)
	);
	// Insert the array, JSON ENCODED, into 'style_formats'
	$init_array['style_formats'] = json_encode( $style_formats );
	return $init_array;
}
// Attach callback to 'tiny_mce_before_init'
add_filter( 'tiny_mce_before_init', 'my_mce_before_init_insert_formats' );