Chrome Version: 70.0.3508.0
OS: Chrome

What steps will reproduce the problem?
(1) Open Youtube app (either in laptop mode or tablet mode)
(2) Play a video and click on the [] button to maximize the video

What is the expected result?
The video should take the entire workspace and hide the shelf

What happens instead?
The shelf was not hidden

There are also some apps that works properly, for example, "Temple Run" works fine: when maximized, it hides its title bar and the shelf. And swipe up on the shelf can bring back the shelf.