[flutter_tools] Launch DevTools with 'v'

[zanderso]

Description

Launch DevTools from the resident runner with 'v' when there is a vm service available.

Related Issues

#41407

Tests

I added the following tests:

I updated tests of the command help.

Breaking Change

Did any tests fail when you ran them? Please read [Handling breaking changes].

• No, no existing tests failed, so this is not a breaking change.

[zanderso]

/cc @jonahwilliams for thoughts on testing. One option would be to wrap the devtools_server methods in an inject-able class, and then verify in existing tests that the methods are called when a mock is injected. wdyt?

[jonahwilliams]

For testing: what I would do is give the ResidentRunner an optional constructor argument:

Future<io.HttpServer> Function({bool enableStdinCommands}) serveDevTools

Then in the launchDevTools method do something like:

await (serveDevTools ?? devtools_server.serveDevTools)(enabledStinCommands: false)

That way we can test it without adding more to the context in the short term

[zanderso]

After further thought, not much of the behavior of the devtools server and its client in the browser can be tested. Instead, I added a test to terminal_handler_test.dart that ensures that ResidentRunner.launchDevTools is called when we get 'v' on the terminal.

[jonahwilliams]

Yeah seems reasonable to me

[jonahwilliams]

LGTM

[jacob314]

This is great.
It would be nice to display a link to this URL in the console rather than
"An Observatory debugger and profiler on iPhone 11 Pro Max is available at:
http:https://127.0.0.1:56450/asdfasdfw=/"
We could provide a link from DevTools to the observatory as an affordance for advanced users who need functionality not yet in DevTools.