Support "once" event listener option

third_party/WebKit/Source/core/events/RegisteredEventListener.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 18 matching lines @@
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class RegisteredEventListener {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
 public:
     RegisteredEventListener()
         : m_useCapture(false)
         , m_passive(false)
+        , m_once(false)
         , m_blockedEventWarningEmitted(false)
         , m_passiveForcedForDocumentTarget(false)
     {
     }
 
     RegisteredEventListener(EventListener* listener, const AddEventListenerOptionsResolved& options)
         : m_listener(listener)
         , m_useCapture(options.capture())
         , m_passive(options.passive())
+        , m_once(options.once())
         , m_blockedEventWarningEmitted(false)
         , m_passiveForcedForDocumentTarget(options.passiveForcedForDocumentTarget())
     {
     }
 
     DEFINE_INLINE_TRACE()
     {
         visitor->trace(m_listener);
     }
 
     AddEventListenerOptionsResolved options() const
     {
         AddEventListenerOptionsResolved result;
         result.setCapture(m_useCapture);
         result.setPassive(m_passive);
         result.setPassiveForcedForDocumentTarget(m_passiveForcedForDocumentTarget);
+        result.setOnce(m_once);
         return result;
     }
 
     const EventListener* listener() const
     {
         return m_listener;
     }
 
     EventListener* listener()
     {
         return m_listener;
     }
 
     bool passive() const
     {
         return m_passive;
     }
 
+    bool once() const
+    {
+        return m_once;
+    }
+
     bool capture() const
     {
         return m_useCapture;
     }
 
     bool blockedEventWarningEmitted() const
     {
         return m_blockedEventWarningEmitted;
     }
 
@@ skipping 20 matching lines @@
         // Equality is soley based on the listener and useCapture flags.
         DCHECK(m_listener);
         DCHECK(other.m_listener);
         return *m_listener == *other.m_listener && m_useCapture == other.m_useCapture;
     }
 
 private:
     Member<EventListener> m_listener;
     unsigned m_useCapture : 1;
     unsigned m_passive : 1;
+    unsigned m_once : 1;
     unsigned m_blockedEventWarningEmitted : 1;
     unsigned m_passiveForcedForDocumentTarget : 1;
 };
 
 } // namespace blink
 
 WTF_ALLOW_CLEAR_UNUSED_SLOTS_WITH_MEM_FUNCTIONS(blink::RegisteredEventListener);
 
 #endif // RegisteredEventListener_h