Cache the result of isScopedInV0 flag in Event object

third_party/WebKit/Source/core/events/Event.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, 2007, 2008 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 224 matching lines @@
         EmptyAfterDispatch,
         NonEmptyAfterDispatch
     };
 
     HeapVector<Member<EventTarget>> pathInternal(ScriptState*, EventPathMode) const;
 
     AtomicString m_type;
     unsigned m_canBubble:1;
     unsigned m_cancelable:1;
     unsigned m_composed:1;
+    unsigned m_isEventTypeScopedInV0:1;
 
     unsigned m_propagationStopped:1;
     unsigned m_immediatePropagationStopped:1;
     unsigned m_defaultPrevented:1;
     unsigned m_defaultHandled:1;
     unsigned m_cancelBubble:1;
     unsigned m_wasInitialized:1;
     unsigned m_isTrusted : 1;
     unsigned m_handlingPassive : 1;
 
     unsigned short m_eventPhase;
     Member<EventTarget> m_currentTarget;
     Member<EventTarget> m_target;
     DOMTimeStamp m_createTime;
     Member<Event> m_underlyingEvent;
     Member<EventPath> m_eventPath;
     // The monotonic platform time in seconds, for input events it is the
     // event timestamp provided by the host OS and reported in the original
     // WebInputEvent instance.
     double m_platformTimeStamp;
 };
 
 #define DEFINE_EVENT_TYPE_CASTS(typeName) \
     DEFINE_TYPE_CASTS(typeName, Event, event, event->is##typeName(), event.is##typeName())
 
 } // namespace blink
 
 #endif // Event_h