LibJS: Don't use MarkedValueList in PromiseValueList

Instead, override visit_edges() and mark the values like any other Cell
subclass would.

This makes PromiseValueList play nice with zombification.

Userland/Libraries/LibJS/Runtime/PromiseConstructor.cpp

@@ -111,7 +111,7 @@ static Value perform_promise_common(GlobalObject& global_object, Object& iterato
             return {};
         }
 
-        values->values.append(js_undefined());
+        values->values().append(js_undefined());
 
         auto next_promise = vm.call(promise_resolve.as_function(), constructor, next_value);
         if (vm.exception())
@@ -135,7 +135,7 @@ static Value perform_promise_all(GlobalObject& global_object, Object& iterator_r
     return perform_promise_common(
         global_object, iterator_record, constructor, result_capability, promise_resolve,
         [&](PromiseValueList& values) -> Value {
-            auto values_array = Array::create_from(global_object, values.values);
+            auto values_array = Array::create_from(global_object, values.values());
 
             (void)vm.call(*result_capability.resolve, js_undefined(), values_array);
             if (vm.exception())
@@ -159,7 +159,7 @@ static Value perform_promise_all_settled(GlobalObject& global_object, Object& it
     return perform_promise_common(
         global_object, iterator_record, constructor, result_capability, promise_resolve,
         [&](PromiseValueList& values) -> Value {
-            auto values_array = Array::create_from(global_object, values.values);
+            auto values_array = Array::create_from(global_object, values.values());
 
             (void)vm.call(*result_capability.resolve, js_undefined(), values_array);
             if (vm.exception())
@@ -186,7 +186,7 @@ static Value perform_promise_any(GlobalObject& global_object, Object& iterator_r
     return perform_promise_common(
         global_object, iterator_record, constructor, result_capability, promise_resolve,
         [&](PromiseValueList& errors) -> Value {
-            auto errors_array = Array::create_from(global_object, errors.values);
+            auto errors_array = Array::create_from(global_object, errors.values());
 
             auto* error = AggregateError::create(global_object);
             error->define_property_or_throw(vm.names.errors, { .value = errors_array, .writable = true, .enumerable = false, .configurable = true });

Userland/Libraries/LibJS/Runtime/PromiseResolvingElementFunctions.cpp

@@ -63,10 +63,10 @@ Value PromiseAllResolveElementFunction::resolve_element()
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
-    m_values.values[m_index] = vm.argument(0);
+    m_values.values()[m_index] = vm.argument(0);
 
     if (--m_remaining_elements.value == 0) {
-        auto values_array = Array::create_from(global_object, m_values.values);
+        auto values_array = Array::create_from(global_object, m_values.values());
         return vm.call(*m_capability.resolve, js_undefined(), values_array);
     }
 
@@ -92,10 +92,10 @@ Value PromiseAllSettledResolveElementFunction::resolve_element()
     object->create_data_property_or_throw(vm.names.status, js_string(vm, "fulfilled"sv));
     object->create_data_property_or_throw(vm.names.value, vm.argument(0));
 
-    m_values.values[m_index] = object;
+    m_values.values()[m_index] = object;
 
     if (--m_remaining_elements.value == 0) {
-        auto values_array = Array::create_from(global_object, m_values.values);
+        auto values_array = Array::create_from(global_object, m_values.values());
         return vm.call(*m_capability.resolve, js_undefined(), values_array);
     }
 
@@ -121,10 +121,10 @@ Value PromiseAllSettledRejectElementFunction::resolve_element()
     object->create_data_property_or_throw(vm.names.status, js_string(vm, "rejected"sv));
     object->create_data_property_or_throw(vm.names.reason, vm.argument(0));
 
-    m_values.values[m_index] = object;
+    m_values.values()[m_index] = object;
 
     if (--m_remaining_elements.value == 0) {
-        auto values_array = Array::create_from(global_object, m_values.values);
+        auto values_array = Array::create_from(global_object, m_values.values());
         return vm.call(*m_capability.resolve, js_undefined(), values_array);
     }
 
@@ -146,10 +146,10 @@ Value PromiseAnyRejectElementFunction::resolve_element()
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
-    m_values.values[m_index] = vm.argument(0);
+    m_values.values()[m_index] = vm.argument(0);
 
     if (--m_remaining_elements.value == 0) {
-        auto errors_array = Array::create_from(global_object, m_values.values);
+        auto errors_array = Array::create_from(global_object, m_values.values());
 
         auto* error = AggregateError::create(global_object);
         error->define_property_or_throw(vm.names.errors, { .value = errors_array, .writable = true, .enumerable = false, .configurable = true });

Userland/Libraries/LibJS/Runtime/PromiseResolvingElementFunctions.h

@@ -24,15 +24,19 @@ struct RemainingElements final : public Cell {
     u64 value { 0 };
 };
 
-struct PromiseValueList final : public Cell {
+class PromiseValueList final : public Cell {
+public:
     PromiseValueList()
-        : values(heap())
     {
     }
 
+    Vector<Value>& values() { return m_values; }
+    Vector<Value> const& values() const { return m_values; }
+
+private:
     virtual const char* class_name() const override { return "PromiseValueList"; }
 
-    MarkedValueList values;
+    Vector<Value> m_values;
 };
 
 class PromiseResolvingElementFunction : public NativeFunction {