Cast functionality is now built into Chrome itself, starting with version 51 of Google's browser. Accessible from the Tools menu, the option renders the dedicated Cast icon almost unnecessary. It'll still be available as an extension, and it'll still work if you have it installed, its sole purpose being to save you one mouse click. What's more, is that you'll no longer be able to set options for resolution, bitrate or quality - these will be set for you automatically depending on content and network quality. Additionally, you'll now be able to mirror a Chrome tab into an ongoing...
Source: http://www.gsmarena.com/chrome_51_has_cast_functionality_builtin_you_can_also_mirror_a_tab_into_hangouts-news-19177.php
