IF you are a fan of using Chrome to cast one of your tabs to a TV, you may be surprised to find that the Cast option is missing. Worse, if you look in places like Chromecast Help on how to Cast a Chrome tab on your TV, you may not find that all that helpful.
Fear not. The Cast option is still there, just hidden. As before, go to the top right of your browser where the three dots are and click on them. Then click on Save and Share… and look for Cast…
Now you can Cast as you did before.
Smart People I Know 
I’m hardly a grand master of UI/UX, but this design choice baffles me.
It is odd! Especially since casting encourages people to buy Chromecasts