Add use counters for lots of DOM APIs.

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

 /*
  * Copyright (C) 2007, 2008 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 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://dev.w3.org/csswg/css-animations/#interface-animationevent
 
 [
     Constructor(DOMString type, optional AnimationEventInit eventInitDict),
 ] interface AnimationEvent : Event {
-    readonly attribute DOMString animationName;
+    [Measure] readonly attribute DOMString animationName;
     // TODO(foolip): elapsedTime should be float.
-    readonly attribute double elapsedTime;
+    [Measure] readonly attribute double elapsedTime;
     // TODO(foolip): readonly attribute DOMString pseudoElement;
 };