The Permissions API allows a web application to be aware of the status of a given permission, to know whether it is granted, denied or if the user will be asked whether the permission should be granted. The purpose of the API is to improve general UX with regards to permissions on the Web, allowing developers to be aware of what is going to happen will enable better flow. Note: mlamouri@chromium.org, timvolodine@chromium.org were the original owners of this feature.
Docs: http://updates.html5rocks.com/2015/04/permissions-api-for-the-web https://developer.mozilla.org/en-US/docs/Web/API/Permissions_API
Samples: https://googlechrome.github.io/samples/permissions/index.html