Initial implementation of WorkletAnimation

third_party/WebKit/Source/modules/compositorworker/WorkletAnimation.idl

+// Copyright 2017 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.
+
+// https://wicg.github.io/animation-worklet/#worklet-animation-desc
+
+enum AnimationPlayState { "idle", "pending", "running" };

[Eric Willigers, 2017/09/01 02:25:23]

AnimationPlayState is already defined
in core/animation/Animation.idl.

I don't understand why any enums need to be defined twice.

The only cases where we currently define an enum twice are
EffectiveConnectionType and RequestCredentials.
In each of those cases (unlike AnimationPlayState),
the two definitions are identical.

[smcgruer, 2017/09/06 19:16:55]

Good point. I was trying to create a restricted enum that only had the types
that I currently support in WorkletAnimation, but there is little point. Removed
this and used Animation::WorkletAnimation in the cpp.

+
+[
+    Constructor(DOMString animatorName,
+                sequence<KeyframeEffectReadOnly> effects,
+                sequence<(DocumentTimeline or ScrollTimeline)> timelines,
+                SerializedScriptValue options),
+    RaisesException=Constructor,
+    RuntimeEnabled=CompositorWorker
+] interface WorkletAnimation {
+  readonly attribute AnimationPlayState playState;
+  void play();
+  void cancel();
+};