In a clean user data directory, if you click the "profile" button at the top right, then click "Sign in", you get a dialog entitled "Sign in to Chrome" with an X at the top-left corner. Focus begins on the X, then immediately moves to a field labelled "Email or phone number". After that, focus is "trapped" inside the signin dialog's webview, and none of the normal methods of dismissing the dialog (hitting Esc, etc) work; also, the close button is not reachable by VO navigation keys.

To escape the dialog, the user has to:
1) Realize that VO reading "inside of a frame 0" indicates that they can traverse out of the AXWebArea via "Stop Interacting"
2) Traverse the VO focus ring in the enclosing "frame 0" to reach the close button

Probably the a11y tree for this dialog should be flattened out so that the close button is part of the inner frame's navigation.