Enumerate the return value of dispatchEvent so it is clear.

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

 /*
  * 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, 2005, 2006, 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 248 matching lines @@
 MouseEventDispatchMediator::MouseEventDispatchMediator(PassRefPtrWillBeRawPtr<MouseEvent> mouseEvent)
     : EventDispatchMediator(mouseEvent)
 {
 }
 
 MouseEvent& MouseEventDispatchMediator::event() const
 {
     return toMouseEvent(EventDispatchMediator::event());
 }
 
-bool MouseEventDispatchMediator::dispatchEvent(EventDispatcher& dispatcher) const
+DispatchEventResult MouseEventDispatchMediator::dispatchEvent(EventDispatcher& dispatcher) const
 {
     MouseEvent& mouseEvent = event();
     if (!mouseEvent.isTrusted()) {
         mouseEvent.eventPath().adjustForRelatedTarget(dispatcher.node(), mouseEvent.relatedTarget());
         return dispatcher.dispatch();
     }
 
     if (isDisabledFormControl(&dispatcher.node()))
-        return false;
+        return DispatchEventResult::CanceledBeforeDispatch;
 
     if (mouseEvent.type().isEmpty())
-        return true; // Shouldn't happen.
+        return DispatchEventResult::NotCanceled; // Shouldn't happen.
 
     ASSERT(!mouseEvent.target() || mouseEvent.target() != mouseEvent.relatedTarget());
 
     EventTarget* relatedTarget = mouseEvent.relatedTarget();
     mouseEvent.eventPath().adjustForRelatedTarget(dispatcher.node(), relatedTarget);
 
-    dispatcher.dispatch();
-    bool swallowEvent = mouseEvent.defaultHandled() || mouseEvent.defaultPrevented();
+    DispatchEventResult dispatchResult = dispatcher.dispatch();
 
     if (mouseEvent.type() != EventTypeNames::click || mouseEvent.detail() != 2)
-        return !swallowEvent;
+        return dispatchResult;
 
     // Special case: If it's a double click event, we also send the dblclick event. This is not part
     // of the DOM specs, but is used for compatibility with the ondblclick="" attribute. This is treated
     // as a separate event in other DOM-compliant browsers like Firefox, and so we do the same.
     RefPtrWillBeRawPtr<MouseEvent> doubleClickEvent = MouseEvent::create();
     doubleClickEvent->initMouseEventInternal(EventTypeNames::dblclick, mouseEvent.bubbles(), mouseEvent.cancelable(), mouseEvent.view(),
         mouseEvent.detail(), mouseEvent.screenX(), mouseEvent.screenY(), mouseEvent.clientX(), mouseEvent.clientY(),
         mouseEvent.modifiers(), mouseEvent.button(), relatedTarget, mouseEvent.sourceCapabilities(), mouseEvent.buttons());
 
     // Inherit the trusted status from the original event.
     doubleClickEvent->setTrusted(mouseEvent.isTrusted());
     if (mouseEvent.defaultHandled())
         doubleClickEvent->setDefaultHandled();
-    EventDispatcher::dispatchEvent(dispatcher.node(), MouseEventDispatchMediator::create(doubleClickEvent));
-    if (doubleClickEvent->defaultHandled() || doubleClickEvent->defaultPrevented())
-        return false;
-    return !swallowEvent;
+    DispatchEventResult doubleClickDispatchResult = EventDispatcher::dispatchEvent(dispatcher.node(), MouseEventDispatchMediator::create(doubleClickEvent));
+    if (doubleClickDispatchResult != DispatchEventResult::NotCanceled)
+        return doubleClickDispatchResult;
+    return dispatchResult;
 }
 
 } // namespace blink