Add support for a modern, asynchronous Clipboard API based on Promises.
The primary motivation for this proposal is to address the following issues present in the current synchronous Clipboard API:
* For security reasons, user agents may need to sanitize images before putting them on the clipboard. This can be time-consuming for large images so it is not reasonable to do it on the main thread. Thus, the current synchronous-nature of the current API prevents images from being supported in some UAs.
* Synchronous APIs restrict the options for getting user permission before performing an action. Some permission models (like the Permissions API) require an async API.
Editor's Draft Clipboard Spec: https://w3c.github.io/clipboard-apis/
Explainer: https://github.com/garykac/clipboard/blob/master/clipboard.md
WICG Discourse: https://discourse.wicg.io/t/proposal-modern-asynchronous-clipboard-api/1513
Comment 1 by garykac@chromium.org
, Dec 29 2016