script: Add new worker globals as debuggees (#38551)

to debug workers in a page with the [SpiderMonkey Debugger
API](https://firefox-source-docs.mozilla.org/js/Debugger/), we need to
pass the worker’s global object to
[Debugger.prototype.**addDebuggee()**](https://firefox-source-docs.mozilla.org/js/Debugger/Debugger.html#adddebuggee-global).
we could pick up the global via the [onNewGlobalObject()
hook](https://firefox-source-docs.mozilla.org/js/Debugger/Debugger.html#onnewglobalobject-global),
but if our script system passes the global to the debugger script
instead, we can later add details like the PipelineId that will help
servo identify debuggees that the API is notifying us about (#38334).

this patch creates a debugger global in worker threads, runs the
debugger script in those new globals, and plumbs new worker globals from
those threads into addDebuggee() via the debugger script. since worker
threads can’t generate PipelineId values, but they only ever run workers
on behalf of one pipeline, we use that pipeline’s PipelineId as the
PipelineId of the debugger global, rather than generating a unique
PipelineId like we do in script threads.

Testing: will undergo many automated tests in #38334
Fixes: part of #36027

Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

components/shared/devtools/lib.rs

@@ -12,7 +12,9 @@
 
 use core::fmt;
 use std::collections::HashMap;
+use std::fmt::Display;
 use std::net::TcpStream;
+use std::str::FromStr;
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 use base::cross_process_instant::CrossProcessInstant;
@@ -488,6 +490,18 @@ impl StartedTimelineMarker {
 }
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
 pub struct WorkerId(pub Uuid);
+impl Display for WorkerId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+impl FromStr for WorkerId {
+    type Err = uuid::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(s.parse()?))
+    }
+}
 
 #[derive(Debug, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]