Use correct signature for custom constructor of CustomEvent

third_party/WebKit/Source/core/events/CustomEvent.idl

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // https://dom.spec.whatwg.org/#interface-customevent
 
 [
     // TODO(bashi): Don't use CustomConstructor. Constructor should be:
     // Constructor(DOMString type, optional CustomEventInit eventInitDict),
-    CustomConstructor,
+    CustomConstructor(DOMString type, optional CustomEventInit eventInitDict),
     Exposed=(Window,Worker),
 ] interface CustomEvent : Event {
     [Custom=Getter] readonly attribute any detail;
 
     [Measure,Custom=(CallEpilogue)] void initCustomEvent(DOMString type, boolean bubbles, boolean cancelable, any detail);
 };