Remove some obsolete entries in Web Animations IDL

third_party/WebKit/Source/core/animation/AnimationTimeline.idl

Index: third_party/WebKit/Source/core/animation/AnimationTimeline.idl
diff --git a/third_party/WebKit/Source/core/animation/AnimationTimeline.idl b/third_party/WebKit/Source/core/animation/AnimationTimeline.idl
index 1358343edb20a2db3d61f3badf36e038616cfcd0..d43ebba4752fb2363fa8c5aeccd33b2e5c68c55d 100644
--- a/third_party/WebKit/Source/core/animation/AnimationTimeline.idl
+++ b/third_party/WebKit/Source/core/animation/AnimationTimeline.idl
@@ -4,14 +4,11 @@
 
 // http://www.w3.org/TR/web-animations/#the-animationtimeline-interface
 
-// TODO(dstockwell): This interface has several changes in the latest spec:
-// https://w3c.github.io/web-animations/#the-animationtimeline-interface
-
 [
     RuntimeEnabled=WebAnimationsAPI,
 ] interface AnimationTimeline {
     attribute double? currentTime;
-    attribute double playbackRate;
-    Animation play(AnimationEffectReadOnly source);
+
+    // TODO(crbug.com/624639): Move getAnimations() to DocumentAnimatable
     sequence<Animation> getAnimations();
 };