Remote page attachments are broken on iOS webviews, or at least in the Google native app and Discover.

All history navigations need to originate from a clicked anchor tag. We should replace our navigation based on the history API, and trigger a click on the anchor tag.

The swipe up interaction we get is not a trusted interaction on Safari (it is on Chrome), but because this is a _self navigation, it won't be blocked by the browser/webview.
This fix has been prototyped and tested already.

cc @ampproject/wg-stories