Enumerate the return value of dispatchEvent so it is clear.

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

Index: third_party/WebKit/Source/core/events/Event.h
diff --git a/third_party/WebKit/Source/core/events/Event.h b/third_party/WebKit/Source/core/events/Event.h
index e447f5d3372663c4dcb7d470fa593c6cb6200c7d..65e2a69ebc6f3401f41fddad3e476b85ebf2cd5b 100644
--- a/third_party/WebKit/Source/core/events/Event.h
+++ b/third_party/WebKit/Source/core/events/Event.h
@@ -201,6 +201,15 @@ public:
 
     void setHandlingPassive(bool value) { m_handlingPassive = value; }
 
+    DispatchEventResult eventResult() const
+    {
+        if (defaultPrevented())
+            return DispatchEventResult::CanceledByEventHandler;
+        if (defaultHandled())
+            return DispatchEventResult::CanceledByDefaultEventHandler;
+        return DispatchEventResult::NotCanceled;
+    }
+
     DECLARE_VIRTUAL_TRACE();
 
 protected: