title: How to cast whole tab to chromecast when there is a cast sender available on page
body: <p>I am adding support for Google Cast sender to a media player and it works as expected so far when casting media from player to chromecast by clicking on cast icon in player. But I am facing problem getting the whole website page/tab to cast to chromecast if the media player with sender app is present on the page. What happens is that when I start a new session from the cast extension button (i.e. click on cast extension button and then click one of the chromecast devices listed in the popup), the sessionListener in my media player's chrome sender app gets called with the session object, and active session is created between player and chromecast. But it takes away the opportunity to browse the website on cast device. Is it possible to cast whole tab when user initiates session by clicking on the cast extension icon even if a sender app is present on the page?</p>