Chrome Version: 61.0.3122.0 (Official Build) canary(64-bit)
OS: Windows 10 Version 1703 (OS Build 16199.1000) 64-bit

What steps will reproduce the problem?

(1) Start Chrome and the NVDA screen reader.
(2) Open the Chrome store page for some extension you do not have installed; e.g. https://chrome.google.com/webstore/detail/violentmonkey/jinjaccalgkegednnccohejagnlnfdag?hl=en-GB
(3) Press the "Add to Chrome" button.
(4) A confirmation dialog will appear. Press NVDA+space to force browse mode for the dialog.
(5) Use the down and up arrow keys to read through the text.

What is the expected result?
The prompt "Add "Violentmonkey"?", followed by the permissions the extension will have, should be reported.

What happens instead?
That text is not reported. Only the buttons are reported.

This occurs because the prompt/permission text is contained within an inner dialog which can never get focus. That inner container should not have a role of dialog, since it isn't focusable and we're already inside a dialog.

Impact: This makes it difficult for most Chrome + NVDA users to review this confirmation prompt, which could be a security concern for those users.
Originally reported in NVDA issue: https://github.com/nvaccess/nvda/issues/6766