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

Source/core/events/CompositionEvent.idl

Index: Source/core/events/CompositionEvent.idl
diff --git a/Source/core/events/CompositionEvent.idl b/Source/core/events/CompositionEvent.idl
index 309c7f38974ae8ff9c2ea6fe5e50c523ace08e04..3d2a209761bc12c8afb15b80608a76ab52e1366a 100644
--- a/Source/core/events/CompositionEvent.idl
+++ b/Source/core/events/CompositionEvent.idl
@@ -33,9 +33,9 @@
     // 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);
 };