Add TODOs to remove AnimationPlayerEvent and AnimationPlayerEventInit

Source/core/events/AnimationPlayerEvent.idl

Index: Source/core/events/AnimationPlayerEvent.idl
diff --git a/Source/core/events/AnimationPlayerEvent.idl b/Source/core/events/AnimationPlayerEvent.idl
index fc05b3e93c0b7073d5716ca06977d9a4fbe34047..bfd724a736b3a3b4366a694dbda18f4c73dabfe7 100644
--- a/Source/core/events/AnimationPlayerEvent.idl
+++ b/Source/core/events/AnimationPlayerEvent.idl
@@ -3,8 +3,9 @@
 // found in the LICENSE file.
 
 // http://www.w3.org/TR/web-animations/#the-animationplayerevent-interface
-// Note: The latest draft removed this event.
-// http://w3c.github.io/web-animations/
+
+// TODO(dstockwell): This interface has been removed in the latest spec:
+// https://w3c.github.io/web-animations/
 
 [
     Constructor(DOMString type, optional AnimationPlayerEventInit eventInitDict),
@@ -13,4 +14,3 @@
     readonly attribute double currentTime;
     readonly attribute double timelineTime;
 };
-