Auto merge of #22121 - gterzian:remove_constellation_block_in_navigation, r=paulrouget

Remove sync constellation -> embedder communication

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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #22042 (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/dom/windowproxy.rs

@@ -93,6 +93,9 @@ pub struct WindowProxy {
 
     /// The parent browsing context's window proxy, if this is a nested browsing context
     parent: Option<Dom<WindowProxy>>,
+
+    /// https://html.spec.whatwg.org/multipage/#delaying-load-events-mode
+    delaying_load_events_mode: Cell<bool>,
 }
 
 impl WindowProxy {
@@ -117,6 +120,7 @@ impl WindowProxy {
             disowned: Cell::new(false),
             frame_element: frame_element.map(Dom::from_ref),
             parent: parent.map(Dom::from_ref),
+            delaying_load_events_mode: Cell::new(false),
             opener,
         }
     }
@@ -312,6 +316,26 @@ impl WindowProxy {
         None
     }
 
+    /// https://html.spec.whatwg.org/multipage/#delaying-load-events-mode
+    pub fn is_delaying_load_events_mode(&self) -> bool {
+        self.delaying_load_events_mode.get()
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#delaying-load-events-mode
+    pub fn start_delaying_load_events_mode(&self) {
+        self.delaying_load_events_mode.set(true);
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#delaying-load-events-mode
+    pub fn stop_delaying_load_events_mode(&self) {
+        self.delaying_load_events_mode.set(false);
+        if let Some(document) = self.document() {
+            if !document.loader().events_inhibited() {
+                ScriptThread::mark_document_with_no_blocked_loads(&document);
+            }
+        }
+    }
+
     // https://html.spec.whatwg.org/multipage/#disowned-its-opener
     pub fn disown(&self) {
         self.disowned.set(true);