Web Animations API: Constructing an Animation from a partial keyframe throws a JS exception

LayoutTests/web-animations-api/element-animate-list-of-keyframes.html

Index: LayoutTests/web-animations-api/element-animate-list-of-keyframes.html
diff --git a/LayoutTests/web-animations-api/element-animate-list-of-keyframes.html b/LayoutTests/web-animations-api/element-animate-list-of-keyframes.html
index fb91feb7b3d1195cc84273546841d7058af9b013..35c06e8e94dbd660dfbd4eb1b061f4f6e3d0eb3b 100644
--- a/LayoutTests/web-animations-api/element-animate-list-of-keyframes.html
+++ b/LayoutTests/web-animations-api/element-animate-list-of-keyframes.html
@@ -51,10 +51,8 @@ test(function() {
 }, 'Calling animate() should start an animation. CamelCase property names should be parsed.');
 
 var keyframesWithInvalid = [
-        {offset: 0.1},
-        {width: '0px', backgroundColor: 'octarine', offset: 0.2},
-        {width: '1000px', foo: 'bar', offset: 1}
-        ];
+        {width: '0px', backgroundColor: 'octarine', offset: 0},
+        {width: '1000px', foo: 'bar', offset: 1}];
 
 test(function() {
     var player = e3.animate(keyframesWithInvalid, {duration: durationValue, fill: 'forwards'});