Fixes an issue where Chromium could crash on a dangling unretained pointer in one of several webRequest functions. This was happening as a result of the fact that we had outstanding blocking requests continue to reference state owned by ProxyingWebsocket and ProxyingURLLoaderFactory after the requests were destroyed.
This had been going on for a few years, and was likely leading to some ongoing memory issues. To fix this, we need to ensure that all state is cleaned up in OnRequestWillBeDestroyed. I chose to create a new BlockedRequest struct to do so, which approximates the approach that upstream takes. The complexities of doing so also made our templated approach more trouble than it felt worth, so i pried that apart into separate handlers.
* fix: web request support proxying websocket
* fix: make tests work
* chore: do not use api:: code outside api/ folder
* chore: do not create proxy when no listener
* test: use separate session to avoid conflicts
* chore: address review
