Enumerate the return value of dispatchEvent so it is clear.

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

Index: third_party/WebKit/Source/core/events/DragEvent.h
diff --git a/third_party/WebKit/Source/core/events/DragEvent.h b/third_party/WebKit/Source/core/events/DragEvent.h
index 86af939a537ba81a74e15420a0fe3b97bffd433a..1e85a8e754e656b057376acb517338d84e228603 100644
--- a/third_party/WebKit/Source/core/events/DragEvent.h
+++ b/third_party/WebKit/Source/core/events/DragEvent.h
@@ -72,7 +72,7 @@ public:
 private:
     explicit DragEventDispatchMediator(PassRefPtrWillBeRawPtr<DragEvent>);
     DragEvent& event() const;
-    bool dispatchEvent(EventDispatcher&) const override;
+    DispatchEventResult dispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(DragEvent);