Restore gesture requirement for async clipboard write access

[ShivanKaul]

Chromium 66+ implements Asynchronous Clipboard API. Chromium, in contrast to Safari and Firefox, allow a website to write to the user's clipboard using navigator.clipboard.writeText()/write() without a user gesture (only criteria is that the tab should be active).

We should require a user gesture (click, touch events) to enable use of navigator.clipboard.writeText() and navigator.clipboard.write(). Else, promise should reject.

Demo website that attempts to write to the user's clipboard: https://shivankaul.com/brave/clipboard-paste.html (if you get a success message, try to paste)

[ShivanKaul]

mozilla/standards-positions#89

[markg85]

Could this be re-evaluated?
Personally i really don't like this clipboard feature at all and want it gone in it's entirety.. That's probably not going to happen so please put it behind a permission request at the very least.

[androolloyd]

Am here to voice concern over this, its incredibly invasive and I would like to see it removed entirely from the Brave engine.