LibWeb: Use HeapFunction for EventLoopPlugin::spin_until

Author: https://github.com/shannonbooth
Commit: 7487a782db
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2062
Reviewed-by: https://github.com/kalenikaliaksandr ✅

Userland/Libraries/LibWeb/FileAPI/FileReader.cpp

@@ -157,9 +157,9 @@ WebIDL::ExceptionOr<void> FileReader::read_operation(Blob& blob, Type type, Opti
 
             // 1. Wait for chunkPromise to be fulfilled or rejected.
             // FIXME: Create spec issue to use WebIDL react to promise steps here instead of this custom logic
-            Platform::EventLoopPlugin::the().spin_until([&]() {
+            Platform::EventLoopPlugin::the().spin_until(JS::create_heap_function(heap(), [promise]() {
                 return promise->state() == JS::Promise::State::Fulfilled || promise->state() == JS::Promise::State::Rejected;
-            });
+            }));
 
             // 2. If chunkPromise is fulfilled, and isFirstChunk is true, queue a task to fire a progress event called loadstart at fr.
             // NOTE: ISSUE 2 We might change loadstart to be dispatched synchronously, to align with XMLHttpRequest behavior. [Issue #119]