Chrome 69 on Mac fullscreen. Toolbar pushes page content down
Go to chrome://flags/#views-browser-windows and select Disabled on the dropdown for the "Use Views browser windows instead of Cocoa" flag. Relaunch Chrome.

This should bring the old behavior back, with one caveat: it will bring the old design back too.

This flag has been removed in chrome 71 so there is no way to change the behavior from 71 onwards