Enumerate the return value of dispatchEvent so it is clear.

third_party/WebKit/Source/core/input/EventHandler.h

Index: third_party/WebKit/Source/core/input/EventHandler.h
diff --git a/third_party/WebKit/Source/core/input/EventHandler.h b/third_party/WebKit/Source/core/input/EventHandler.h
index 0674625268707e3dcfe469af9634a3b4d7956b3e..020233322a54bcd5d1f52c2765a95630f8356741 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.h
+++ b/third_party/WebKit/Source/core/input/EventHandler.h
@@ -179,7 +179,13 @@ public:
     void setMouseDownMayStartAutoscroll() { m_mouseDownMayStartAutoscroll = true; }
 
     static WebInputEventResult mergeEventResult(WebInputEventResult resultA, WebInputEventResult resultB);
-    static WebInputEventResult eventToEventResult(PassRefPtrWillBeRawPtr<Event>, bool);
+    static WebInputEventResult toWebInputEventResult(DispatchEventResult);
+
+    // Convert |result| into a WebInputEventResult apply asserts for
+    // cases that should not happen in the specified DOM dispatch event model.
+    // Specifically assert failure on DispatchEventResult::CanceledDefaultEventHandler
+    // and DispatchEventResult::CanceledBeforeDispatch.
+    static WebInputEventResult toWebInputEventResultWithStrictAsserts(DispatchEventResult);
 
     static PlatformEvent::Modifiers accessKeyModifiers();
     bool handleAccessKey(const PlatformKeyboardEvent&);