[wrapper-tracing] Support for incrementally tracing ScopedPersistent

third_party/WebKit/Source/core/events/EventTarget.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ skipping 140 matching lines @@
 
 DEFINE_TRACE(EventTargetData) {
   visitor->trace(eventListenerMap);
 }
 
 DEFINE_TRACE_WRAPPERS(EventTarget) {
   EventListenerIterator iterator(const_cast<EventTarget*>(this));
   while (EventListener* listener = iterator.nextListener()) {
     if (listener->type() != EventListener::JSEventListenerType)
       continue;
-    V8AbstractEventListener* v8listener =
-        static_cast<V8AbstractEventListener*>(listener);
-    if (!v8listener->hasExistingListenerObject())
-      continue;
-
-    visitor->traceWrappers(v8listener);
+    visitor->traceWrappers(static_cast<V8AbstractEventListener*>(listener));
   }
 }
 
 EventTarget::EventTarget() {}
 
 EventTarget::~EventTarget() {}
 
 Node* EventTarget::toNode() {
   return nullptr;
 }
@@ skipping 121 matching lines @@
     argv.append(toNode() ? toNode()->nodeName() : interfaceName());
     argv.append(eventType);
     activityLogger->logEvent("blinkAddEventListener", argv.size(), argv.data());
   }
 
   RegisteredEventListener registeredListener;
   bool added = ensureEventTargetData().eventListenerMap.add(
       eventType, listener, options, &registeredListener);
   if (added) {
     if (listener->type() == EventListener::JSEventListenerType) {
-      V8AbstractEventListener* v8listener =
-          static_cast<V8AbstractEventListener*>(listener);
-      if (v8listener->hasExistingListenerObject())
-        ScriptWrappableVisitor::writeBarrier(this, v8listener);
+      ScriptWrappableVisitor::writeBarrier(
+          this, static_cast<V8AbstractEventListener*>(listener));
     }
     addedEventListener(eventType, registeredListener);
   }
   return added;
 }
 
 void EventTarget::addedEventListener(
     const AtomicString& eventType,
     RegisteredEventListener& registeredListener) {
   if (eventType == EventTypeNames::auxclick) {
@@ skipping 444 matching lines @@
   // they have one less listener to invoke.
   if (d->firingEventIterators) {
     for (size_t i = 0; i < d->firingEventIterators->size(); ++i) {
       d->firingEventIterators->at(i).iterator = 0;
       d->firingEventIterators->at(i).end = 0;
     }
   }
 }
 
 }  // namespace blink