More work towards async drag and drop support for blobs on iOS/macOS.
Created attachment 330261 [details]
Depends on https://bugs.webkit.org/show_bug.cgi?id=181189
Created attachment 330352 [details]
v2 (blocked by https://bugs.webkit.org/show_bug.cgi?id=181189)
On further investigation, I don't think it's possible to implement attachment dragging support through this mechanism, given that there's no way on iOS to tell when the destination app is finished accepting data on drop.
As such, we can't cache any information any information in the UI process because it's not possible to know when it's safe to clean up the cached data.
I need to rethink this...