Google vowed that Android users would finally get official screen mirroring on Chromecast through an update, and it's making good on that promise by rolling out the Chromecast 1.7 app today. Grab the new release and supporting devices (primarily from HTC, LG and Samsung) can send just about anything to a TV just by hitting a "cast screen" button. If you're using a Nexus device, you don't even have to launch any software -- the feature will pop up in Android's quick settings. You're high and dry if your devices aren't on Google's compatibility list, but don't worry too much. We hear there are third-party mirroring apps that can pick up the slack.