* Added support for authentication codes for the VM service.
Previously, a valid web socket connection would use the following URI:
`ws://127.0.0.1/ws`
Now, by default, the VM service requires a connection to be made with a
URI similar to the following:
`ws://127.0.0.1:8181/Ug_U0QVsqFs=/ws`
where `Ug_U0QVsqFs` is an authentication code generated and shared by
the
service.
This behavior can be disabled with the `--disable-service-auth-codes`
flag.
For some reaosn, when we discovered our URI, we were re-instantiating
the `Completer` instance variable whose future we listen to in `nextUri()`.
This led to a race between a caller calling `nextUri()` and us discovering
the URI. If we happened to discover our URI before a caller called
`nextUri()`, then they would be left waiting on a future from the newly
allocated `Completer` (which would never complete).
Fixes#10064
1. Add `PortScanner` abstraction so that we don't do actual port scanning
in tests.
2. Don't change the real `cwd` of the isolate during tests, as it affects
all tests, not just the current running test.
Fixes#8761
This moves the various copies of port forwarding code in the Device subclasses into the ProtocolDiscovery class.
* move port forwarding to a common location
* throw exception if protocol Uri is not discovered or port forwarding fails
* cancel discovery protocol subscriptions on iOS launches (wasn't happening before)
* fix iOS port forwarding to match other implementations
* add tests
* rename service_protocol.dart to protocol_discovery.dart
* add a wrapper around the obs. protocol
* use json-rpc in run
* consolidate obs. code; implement flutter run --benchmark
* review comments
