void EventListenerInfo::getEventListeners(EventTarget* target, WillBeHeapVector<EventListenerInfo>& eventInformation, bool includeAncestors)
{
    // The Node's Ancestors including self.
    WillBeHeapVector<RawPtrWillBeMember<EventTarget>> ancestors;
    ancestors.append(target);
    if (includeAncestors) {
        Node* node = target->toNode();
        for (ContainerNode* ancestor = node ? node->parentOrShadowHostNode() : nullptr; ancestor; ancestor = ancestor->parentOrShadowHostNode())
            ancestors.append(ancestor);
    }

    // Nodes and their Listeners for the concerned event types (order is top to bottom)
    for (size_t i = ancestors.size(); i; --i) {
        EventTarget* ancestor = ancestors[i - 1];
        Vector<AtomicString> eventTypes = ancestor->eventTypes();
        for (size_t j = 0; j < eventTypes.size(); ++j) {
            AtomicString& type = eventTypes[j];
            EventListenerVector* listeners = ancestor->getEventListeners(type);
            if (!listeners)
                continue;
            EventListenerVector filteredListeners;
            filteredListeners.reserveCapacity(listeners->size());
            for (size_t k = 0; k < listeners->size(); ++k) {
                if (listeners->at(k).listener->type() == EventListener::JSEventListenerType)
                    filteredListeners.append(listeners->at(k));
            }
            if (!filteredListeners.isEmpty())
                eventInformation.append(EventListenerInfo(ancestor, type, filteredListeners));
        }
    }
}
void EventHandlerRegistry::updateAllEventHandlers(ChangeOperation op, EventTarget& target)
{
    if (!target.hasEventListeners())
        return;

    Vector<AtomicString> eventTypes = target.eventTypes();
    for (size_t i = 0; i < eventTypes.size(); ++i) {
        EventHandlerClass handlerClass;
        if (!eventTypeToClass(eventTypes[i], &handlerClass))
            continue;
        if (op == RemoveAll) {
            updateEventHandlerInternal(op, handlerClass, &target);
            continue;
        }
        for (unsigned count = target.getEventListeners(eventTypes[i]).size(); count > 0; --count)
            updateEventHandlerInternal(op, handlerClass, &target);
    }
}