Enumerate the return value of dispatchEvent so it is clear.

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 183 matching lines @@
     // ErrorEvent behaves, can override this method.
     virtual bool canBeDispatchedInWorld(const DOMWrapperWorld&) const { return true; }
 
     virtual PassRefPtrWillBeRawPtr<EventDispatchMediator> createMediator();
 
     bool isTrusted() const { return m_isTrusted; }
     void setTrusted(bool value) { m_isTrusted = value; }
 
     void setHandlingPassive(bool value) { m_handlingPassive = value; }
 
+    DispatchEventResult eventResult() const

[philipj_slow, 2016/02/25 15:23:46]

dispatchEventResult or dispatchResult? The result is not of the event, but of a
specific dispatch. If you could make this a free function
dispatchEventResult(const Event& event) in EventTarget.h that would also assert
that the event has already been dispatched, that might be nice. (Or not, you be
the judge.)

[dtapuska, 2016/02/25 22:06:10]

Done.

+    {
+        if (defaultPrevented())
+            return DispatchEventResult::CanceledByEventHandler;
+        if (defaultHandled())
+            return DispatchEventResult::CanceledByDefaultEventHandler;
+        return DispatchEventResult::NotCanceled;
+    }
+
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     Event();
     Event(const AtomicString& type, bool canBubble, bool cancelable);
     Event(const AtomicString& type, bool canBubble, bool cancelable, double platformTimeStamp);
     Event(const AtomicString& type, bool canBubble, bool cancelable, bool scoped);
     Event(const AtomicString& type, bool canBubble, bool cancelable, bool scoped, double platformTimeStamp);
     Event(const AtomicString& type, const EventInit&);
 
@@ skipping 27 matching lines @@
     // 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