Auto merge of #16506 - cbrewster:about_chaos, r=asajeffrey

Make non-initial about:blank loads async

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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 fix #14856 (github issue number if applicable).

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components/script/dom/window.rs

@@ -1537,10 +1537,10 @@ impl Window {
                 }
         }
 
+        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
         self.main_thread_script_chan().send(
-            MainThreadScriptMsg::Navigate(self.upcast::<GlobalScope>().pipeline_id(),
-                LoadData::new(url, referrer_policy, Some(doc.url())),
-                replace)).unwrap();
+            MainThreadScriptMsg::Navigate(pipeline_id,
+                LoadData::new(url, Some(pipeline_id), referrer_policy, Some(doc.url())), replace)).unwrap();
     }
 
     pub fn handle_fire_timer(&self, timer_id: TimerEventId) {