Auto merge of #14173 - asajeffrey:script-thread-stores-top-level-frame-id, r=paulrouget

Report panics using the top-level frame id rather than the pipeline id

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At the moment, we report panics from script and layout using the root pipeline id. Once we are sharing more script threads, there won't be a root pipeline id any more. The plan is only to share script threads in the same tab, so there will be a top-level frame id that all the pipelines have in common. This PR reports panics using that top-level frame id.

This mostly makes a difference to the browser API: rather than targeting a `mozbrowsererror` event at the root iframe of the script thread that panicked, it targets it at the containing mozbrowser iframe.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because we don't test crash reporting

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components/script/dom/dedicatedworkerglobalscope.rs

@@ -26,7 +26,7 @@ use js::jsapi::{HandleValue, JS_SetInterruptCallback};
 use js::jsapi::{JSAutoCompartment, JSContext};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
-use msg::constellation_msg::PipelineId;
+use msg::constellation_msg::FrameId;
 use net_traits::{IpcSend, load_whole_resource};
 use net_traits::request::{CredentialsMode, Destination, RequestInit, Type as RequestType};
 use rand::random;
@@ -158,9 +158,14 @@ impl DedicatedWorkerGlobalScope {
                             closing: Arc<AtomicBool>) {
         let serialized_worker_url = worker_url.to_string();
         let name = format!("WebWorker for {}", serialized_worker_url);
+        let top_level_frame_id = FrameId::installed();
+
         spawn_named(name, move || {
             thread_state::initialize(thread_state::SCRIPT | thread_state::IN_WORKER);
-            PipelineId::install(init.pipeline_id);
+
+            if let Some(top_level_frame_id) = top_level_frame_id {
+                FrameId::install(top_level_frame_id);
+            }
 
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);