Support DevTools extensions embedded inside VS Code

[kenzieschmoll]

As of flutter/devtools@0fba400, DevTools extensions are now shown in the debug session DevTools menu:

This extension screens open by default in the browser. What will it take to enable extension screens to be opened inside VS code like other devtools screens are?

[DanTup]

@kenzieschmoll is there anything special I need to do for this to show up? I'm on latest DevTools and I see my extension when I click "Open in Browser" from the sidebar, but it doesn't show up in the menu itself:

I had a look through flutter/devtools@0fba400 but didn't spot any obvious reason for this.

[DanTup]

embedded_extensions.mp4

[DanTup]

@kenzieschmoll this is in today's pre-release (3.81.20240130) if you want to try it out.

It inherits the default setting from dart.devToolsLocation but
because of #4387 you can control it individually:

"dart.devToolsLocation": {
	"default": "beside", // default for unlisted pages
	"inspector": "active", // built-in page
	"danny_library_ext": "external", // extension page
}

The default setting remains that everything is "beside" (eg. open a second tab next to the active one).