web-share permission policy

"web-share" is being added to the Web Share API spec in
w3c/web-share#151

Blink support is being implemented in
https://chromium-review.googlesource.com/c/chromium/src/+/2299791

features.md

@@ -49,6 +49,7 @@ integrated into their respective specs.
 | ------------ | --------------- | --------------- |
 | Client Hints<sup>[3](#fn3)</sup> | https://github.com/w3c/webappsec-feature-policy/issues/129 | |
 | `geolocation` | https://github.com/w3c/permissions/pull/163 | [Chrome 64](https://www.chromestatus.com/feature/5023919287304192) |
+| `web-share` | https://github.com/w3c/web-share/pull/166 | [Planned for Chrome 86](https://chromium-review.googlesource.com/c/chromium/src/+/2299791) |
 
 ## Experimental Features