Chrome Version: 65.0.3325.209 (Official Build) (64-bit)
OS: CrOS [Mozilla/5.0 (X11; CrOS x86_64 10323.67.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.209 Safari/537.36], although I think I saw this on Linux as well (can check later today)

What steps will reproduce the problem?
(1) Open a(n incognito) tab
(2) Search for something on google.com (e.g. through the omnibar)
(3) Wait long enough to get the 'google.com wants to know your location' dialog to open
(4) try to close the tab using the keyboard

What is the expected result?

Ctrl+W still closes the tab, without allowing the requested permission(s)

What happens instead?

Nothing, the dialog prevents Ctrl+W from closing the tab. (clicking the X on the tab while ignoring the permissions dialog still works)