Web Animations: Update naming to reflect spec changes

Source/core/animation/Timing.idl

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// http://www.w3.org/TR/web-animations/#the-animationtiming-interface
-
-// TODO(dstockwell): This interface does not exist in the latest spec, which
-// instead has a AnimationEffectTimingReadonly interface:
-// https://w3c.github.io/web-animations/#the-animationeffecttimingreadonly-interface
-
-[
-    ImplementedAs=AnimationNodeTiming,
-    RuntimeEnabled=WebAnimationsAPI,
-    WillBeGarbageCollected,
-] interface Timing {
-    attribute double delay;
-    attribute double endDelay;
-    attribute DOMString fill;
-    attribute double iterationStart;
-    attribute unrestricted double iterations;
-    attribute (unrestricted double or DOMString) duration;
-    attribute double playbackRate;
-    attribute DOMString direction;
-    attribute DOMString easing;
-};