LibWeb/IndexedDB: Remove spin_until from checking finished transactions

Author: https://github.com/Lubrsi
Commit: https://github.com/LadybirdBrowser/ladybird/commit/d87c2a55b00
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6182

Libraries/LibWeb/IndexedDB/Internal/IDBTransactionObserver.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025, Luke Wilde <luke@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibGC/Cell.h>
+#include <LibGC/CellAllocator.h>
+#include <LibWeb/Forward.h>
+
+namespace Web::IndexedDB {
+
+class IDBTransactionObserver final : public GC::Cell {
+    GC_CELL(IDBTransactionObserver, GC::Cell);
+    GC_DECLARE_ALLOCATOR(IDBTransactionObserver);
+
+public:
+    virtual ~IDBTransactionObserver();
+
+    [[nodiscard]] GC::Ptr<GC::Function<void()>> transaction_finished_observer() const { return m_transaction_finished_observer; }
+    void set_transaction_finished_observer(GC::Ptr<GC::Function<void()>> callback) { m_transaction_finished_observer = callback; }
+
+    GC::Ref<IDBTransaction> transaction() const { return m_transaction; }
+
+    void unobserve();
+
+private:
+    explicit IDBTransactionObserver(IDBTransaction&);
+
+    virtual void visit_edges(Cell::Visitor&) override;
+    virtual void finalize() override;
+
+    bool m_observing { false };
+
+    GC::Ref<IDBTransaction> m_transaction;
+    GC::Ptr<GC::Function<void()>> m_transaction_finished_observer;
+};
+
+}