LibWeb: Add a DocumentObserver hook to be notified of readyState changes

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -2392,6 +2392,11 @@ void Document::update_readiness(HTML::DocumentReadyState readiness_value)
             m_needs_to_call_page_did_load = true;
         }
     }
+
+    for (auto document_observer : m_document_observers) {
+        if (document_observer->document_readiness_observer())
+            document_observer->document_readiness_observer()->function()(m_readiness);
+    }
 }
 
 // https://html.spec.whatwg.org/multipage/dom.html#dom-document-lastmodified

Userland/Libraries/LibWeb/DOM/DocumentObserver.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2023-2024, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -25,6 +25,7 @@ void DocumentObserver::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_document);
     visitor.visit(m_document_became_inactive);
     visitor.visit(m_document_completely_loaded);
+    visitor.visit(m_document_readiness_observer);
 }
 
 void DocumentObserver::finalize()
@@ -43,4 +44,9 @@ void DocumentObserver::set_document_completely_loaded(Function<void()> callback)
     m_document_completely_loaded = JS::create_heap_function(vm().heap(), move(callback));
 }
 
+void DocumentObserver::set_document_readiness_observer(Function<void(HTML::DocumentReadyState)> callback)
+{
+    m_document_readiness_observer = JS::create_heap_function(vm().heap(), move(callback));
+}
+
 }

Userland/Libraries/LibWeb/DOM/DocumentObserver.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2023-2024, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -11,6 +11,7 @@
 #include <LibJS/SafeFunction.h>
 #include <LibWeb/Bindings/PlatformObject.h>
 #include <LibWeb/Forward.h>
+#include <LibWeb/HTML/DocumentReadyState.h>
 
 namespace Web::DOM {
 
@@ -25,6 +26,9 @@ public:
     [[nodiscard]] JS::GCPtr<JS::HeapFunction<void()>> document_completely_loaded() const { return m_document_completely_loaded; }
     void set_document_completely_loaded(Function<void()>);
 
+    [[nodiscard]] JS::GCPtr<JS::HeapFunction<void(HTML::DocumentReadyState)>> document_readiness_observer() const { return m_document_readiness_observer; }
+    void set_document_readiness_observer(Function<void(HTML::DocumentReadyState)>);
+
 private:
     explicit DocumentObserver(JS::Realm&, DOM::Document&);
 
@@ -34,6 +38,7 @@ private:
     JS::NonnullGCPtr<DOM::Document> m_document;
     JS::GCPtr<JS::HeapFunction<void()>> m_document_became_inactive;
     JS::GCPtr<JS::HeapFunction<void()>> m_document_completely_loaded;
+    JS::GCPtr<JS::HeapFunction<void(HTML::DocumentReadyState)>> m_document_readiness_observer;
 };
 
 }