Version: 56.0.2895.0
OS: 10.11

What steps will reproduce the problem?
(1) With VoiceOver enabled and at least two visible Chrome windows open, bring up a basic auth dialog (e.g. https://auth-demo.aerobatic.io/protected-standard/).
(2) Use cmd+` to switch to another window.
(3) Use cmd+` to switch back to the first window.

What is the expected output?
The basic auth dialog still has VoiceOver focus.

What do you see instead?
The window behind the dialog now has focus, and there's no obvious way to get back to the dialog. It *is* possible through the window switcher (VO-(F2,F2)), but the window will show up here as three windows (the main window, the dialog, and a "ghost" window).

Safari behaves better here — the basic auth dialog is "modal" and always gets VO focus in the window until it's dismissed, and the whole thing shows up as a single window.