error handling for aborted streams feeding a navigation request

[wanderview]

This demo streams data every 1 second from a service worker infinitely:

https://html-sw-stream.glitch.me/

Chrome will currently eventually time out the service worker. When this happens the partially rendered iframe is just left.

Aside from the question in #1182, should aborting the service worker in the middle of the stream leave the partially rendered data? Should we not show an error here?

[jakearchibald]

What do we do without a service worker in these cases? I thought we still show partial data if the connection terminates.

[wanderview]

I tried running edge 16 through this test, but it doesn't seem to stream data for any of the iframes.

[wanderview]

I retested in FF58 and chrome 61. I left them both up for 10+ minutes:

Chrome:

• No service worker iframe continues to stream without timeout
• Service worker iframe with server stream times out at 330 seconds
• Service worker iframe with js stream times out at 330 seconds

Firefox:

• No service worker iframe continues to stream without timeout
• Service worker iframe with server stream continues to stream without timeout
• Service worker iframe with js stream times out at 330 seconds

In both browsers the "timeout" leaves the iframe with partial data.

I guess maybe the original issue is moot since we are aligned now.

Do we care about the difference in the middle iframe? I think the FF behavior is due to us bypassing the SW completely for the data copying in that case which means killing the SW doesn't have any effect. That may change with our multi-process refactor (if the process is killed, etc.).