Facebook announced a new video chat capability it will roll out in conjunction with Skype, in what the social-networking giant said is the first of many announcements of new applications to come in the next couple of months. Users will be able to click a button in Facebook to call a friend. If the friend does not already have the plugin required for video chat, the friend will see a pop-up to download the plugin. That download should just take 10 or 20 seconds, said Mark Zuckerberg, Facebook’s CEO, during a webcast press conference.