Add UseCounters for init*Event methods that aren't already measured

Source/core/events/CompositionEvent.idl

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * 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 15 matching lines @@
 // https://w3c.github.io/uievents/#interface-CompositionEvent
 
 [
     Constructor(DOMString type, optional CompositionEventInit eventInitDict),
 ] interface CompositionEvent : UIEvent {
     readonly attribute DOMString data;
 
     // https://w3c.github.io/uievents/#idl-interface-CompositionEvent-initializers
     // TODO(philipj): None of the initCompositionEvent() arguments should be
     // optional, and the spec has a locale argument after data.
-    void initCompositionEvent([Default=Undefined] optional DOMString type,
-                              [Default=Undefined] optional boolean bubbles,
-                              [Default=Undefined] optional boolean cancelable,
-                              [Default=Undefined] optional Window? view,
-                              [Default=Undefined] optional DOMString data);
+    [Measure] void initCompositionEvent([Default=Undefined] optional DOMString type,
+                                        [Default=Undefined] optional boolean bubbles,
+                                        [Default=Undefined] optional boolean cancelable,
+                                        [Default=Undefined] optional Window? view,
+                                        [Default=Undefined] optional DOMString data);
 };