[v8 gc] Introduce a base class for all objects that can have pending activity

third_party/WebKit/Source/modules/notifications/Notification.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 98 matching lines @@
 {
     Notification* notification = new Notification(context, data);
     notification->setPersistentId(persistentId);
     notification->setState(showing ? NotificationStateShowing : NotificationStateClosed);
     notification->suspendIfNeeded();
 
     return notification;
 }
 
 Notification::Notification(ExecutionContext* context, const WebNotificationData& data)
-    : ActiveDOMObject(context)
+    : ActiveScriptWrappable(this)
+    , ActiveDOMObject(context)
     , m_data(data)
     , m_persistentId(kInvalidPersistentId)
     , m_state(NotificationStateIdle)
     , m_asyncRunner(AsyncMethodRunner<Notification>::create(this, &Notification::show))
 {
     ASSERT(notificationManager());
 }
 
 Notification::~Notification()
 {
@@ skipping 253 matching lines @@
 }
 
 DEFINE_TRACE(Notification)
 {
     visitor->trace(m_asyncRunner);
     RefCountedGarbageCollectedEventTargetWithInlineData<Notification>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink