/// <summary>
/// Figure out if any video files are unused in this book, in case we haven't had them stripped out by opening
/// the saved book yet (when BookStorage will do it for us).
/// </summary>
/// <param name="book"></param>
/// <returns></returns>
internal static IEnumerable <string> GetVideoFilesToInclude(Book.Book book)
{
return(BookStorage.GetVideoPathsRelativeToBook(book.RawDom.DocumentElement));
}
