--- a/testing/web-platform/tests/web-animations/interfaces/KeyframeEffect/processing-a-keyframes-argument.html
+++ b/testing/web-platform/tests/web-animations/interfaces/KeyframeEffect/processing-a-keyframes-argument.html
@@ -40,17 +40,17 @@ const gNonAnimatableProps = [
   'font-size', // Supported property that uses dashes
 ];
 
 function TestKeyframe(testProp) {
   let _propAccessCount = 0;
 
   Object.defineProperty(this, testProp, {
     get: function() { _propAccessCount++; },
-    enumerable: true
+    enumerable: true,
   });
 
   Object.defineProperty(this, 'propAccessCount', {
     get: function() { return _propAccessCount; }
   });
 }
 
 function GetTestKeyframeSequence(testProp) {
@@ -92,65 +92,65 @@ function assertEquivalentKeyframeSyntax(
 const gEquivalentSyntaxTests = [
   {
     description: 'two properties with one value',
     indexedKeyframes: {
       left: '100px',
       opacity: ['1'],
     },
     sequencedKeyframes: [
-      {left: '100px', opacity: '1'},
+      { left: '100px', opacity: '1' },
     ],
   },
   {
     description: 'two properties with three values',
     indexedKeyframes: {
       left: ['10px', '100px', '150px'],
       opacity: ['1', '0', '1'],
     },
     sequencedKeyframes: [
-      {left: '10px', opacity: '1'},
-      {left: '100px', opacity: '0'},
-      {left: '150px', opacity: '1'},
+      { left: '10px', opacity: '1' },
+      { left: '100px', opacity: '0' },
+      { left: '150px', opacity: '1' },
     ],
   },
   {
     description: 'two properties with different numbers of values',
     indexedKeyframes: {
       left: ['0px', '100px', '200px'],
       opacity: ['0', '1']
     },
     sequencedKeyframes: [
-      {left: '0px', opacity: '0'},
-      {left: '100px'},
-      {left: '200px', opacity: '1'},
+      { left: '0px', opacity: '0' },
+      { left: '100px' },
+      { left: '200px', opacity: '1' },
     ],
   },
   {
     description: 'same easing applied to all keyframes',
     indexedKeyframes: {
       left: ['10px', '100px', '150px'],
       opacity: ['1', '0', '1'],
       easing: 'ease',
     },
     sequencedKeyframes: [
-      {left: '10px', opacity: '1', easing: 'ease'},
-      {left: '100px', opacity: '0', easing: 'ease'},
-      {left: '150px', opacity: '1', easing: 'ease'},
+      { left: '10px', opacity: '1', easing: 'ease' },
+      { left: '100px', opacity: '0', easing: 'ease' },
+      { left: '150px', opacity: '1', easing: 'ease' },
     ],
   },
   {
     description: 'same composite applied to all keyframes',
     indexedKeyframes: {
       left: ['0px', '100px'],
       composite: 'add',
     },
     sequencedKeyframes: [
-      {left: '0px', composite: 'add'},
-      {left: '100px', composite: 'add'},
+      { left: '0px', composite: 'add' },
+      { left: '100px', composite: 'add' },
     ],
   },
 ];
 
 for (const {description, indexedKeyframes, sequencedKeyframes} of
      gEquivalentSyntaxTests) {
   test(function(t) {
     assertEquivalentKeyframeSyntax(indexedKeyframes, sequencedKeyframes);
@@ -169,162 +169,168 @@ function createIterable(iterations) {
         },
       };
     },
   };
 }
 
 test(() => {
   const effect = new KeyframeEffect(null, createIterable([
-    {done: false, value: {left: '100px'}},
-    {done: false, value: {left: '300px'}},
-    {done: false, value: {left: '200px'}},
-    {done: true},
+    { done: false, value: { left: '100px' } },
+    { done: false, value: { left: '300px' } },
+    { done: false, value: { left: '200px' } },
+    { done: true },
   ]));
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', left: '100px'},
-    {offset: null, computedOffset: 0.5, easing: 'linear', left: '300px'},
-    {offset: null, computedOffset: 1, easing: 'linear', left: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', left: '100px' },
+    { offset: null, computedOffset: 0.5, easing: 'linear', left: '300px' },
+    { offset: null, computedOffset: 1, easing: 'linear', left: '200px' },
   ]);
 }, 'Keyframes are read from a custom iterator');
 
 test(() => {
   const keyframes = createIterable([
-    {done: false, value: {left: '100px'}},
-    {done: false, value: {left: '300px'}},
-    {done: false, value: {left: '200px'}},
-    {done: true},
+    { done: false, value: { left: '100px' } },
+    { done: false, value: { left: '300px' } },
+    { done: false, value: { left: '200px' } },
+    { done: true },
   ]);
   keyframes.easing = 'ease-in-out';
   keyframes.offset = '0.1';
   const effect = new KeyframeEffect(null, keyframes);
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', left: '100px'},
-    {offset: null, computedOffset: 0.5, easing: 'linear', left: '300px'},
-    {offset: null, computedOffset: 1, easing: 'linear', left: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', left: '100px' },
+    { offset: null, computedOffset: 0.5, easing: 'linear', left: '300px' },
+    { offset: null, computedOffset: 1, easing: 'linear', left: '200px' },
   ]);
 }, "'easing' and 'offset' are ignored on iterable objects");
 
 test(() => {
   const effect = new KeyframeEffect(null, createIterable([
-    {done: false, value: {left: '100px', top: '200px'}},
-    {done: false, value: {left: '300px'}},
-    {done: false, value: {left: '200px', top: '100px'}},
-    {done: true},
+    { done: false, value: { left: '100px', top: '200px' } },
+    { done: false, value: { left: '300px' } },
+    { done: false, value: { left: '200px', top: '100px' } },
+    { done: true },
   ]));
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', left: '100px', top: '200px'},
-    {offset: null, computedOffset: 0.5, easing: 'linear', left: '300px'},
-    {offset: null, computedOffset: 1, easing: 'linear', left: '200px', top: '100px'},
+    { offset: null, computedOffset: 0, easing: 'linear', left: '100px',
+      top: '200px' },
+    { offset: null, computedOffset: 0.5, easing: 'linear', left: '300px' },
+    { offset: null, computedOffset: 1, easing: 'linear', left: '200px',
+      top: '100px' },
   ]);
 }, 'Keyframes are read from a custom iterator with multiple properties'
    + ' specified');
 
 test(() => {
   const effect = new KeyframeEffect(null, createIterable([
-    {done: false, value: {left: '100px'}},
-    {done: false, value: {left: '250px', offset: 0.75}},
-    {done: false, value: {left: '200px'}},
-    {done: true},
+    { done: false, value: { left: '100px' } },
+    { done: false, value: { left: '250px', offset: 0.75 } },
+    { done: false, value: { left: '200px' } },
+    { done: true },
   ]));
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', left: '100px'},
-    {offset: 0.75, computedOffset: 0.75, easing: 'linear', left: '250px'},
-    {offset: null, computedOffset: 1, easing: 'linear', left: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', left: '100px' },
+    { offset: 0.75, computedOffset: 0.75, easing: 'linear', left: '250px' },
+    { offset: null, computedOffset: 1, easing: 'linear', left: '200px' },
   ]);
 }, 'Keyframes are read from a custom iterator with where an offset is'
    + ' specified');
 
 test(() => {
-  assert_throws({name: 'TypeError'}, function() {
+  assert_throws({ name: 'TypeError' }, function() {
     new KeyframeEffect(null, createIterable([
-      {done: false, value: {left: '100px'}},
-      {done: false, value: 1234},
-      {done: false, value: {left: '200px'}},
-      {done: true},
+      { done: false, value: { left: '100px' } },
+      { done: false, value: 1234 },
+      { done: false, value: { left: '200px' } },
+      { done: true },
     ]));
   });
 }, 'Reading from a custom iterator that returns a non-object keyframe'
    + ' should throw');
 
 test(() => {
   const effect = new KeyframeEffect(null, createIterable([
-    {done: false, value: {left: ['100px', '200px']}},
-    {done: true},
+    { done: false, value: { left: ['100px', '200px'] } },
+    { done: true },
   ]));
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 1, easing: 'linear'}
+    { offset: null, computedOffset: 1, easing: 'linear' }
   ]);
 }, 'A list of values returned from a custom iterator should be ignored');
 
 test(function(t) {
   const keyframe = {};
-  Object.defineProperty(keyframe, 'width', {value: '200px'});
+  Object.defineProperty(keyframe, 'width', { value: '200px' });
   Object.defineProperty(keyframe, 'height', {
     value: '100px',
-    enumerable: true});
+    enumerable: true,
+  });
   assert_equals(keyframe.width, '200px', 'width of keyframe is readable');
   assert_equals(keyframe.height, '100px', 'height of keyframe is readable');
 
-  const effect = new KeyframeEffect(null, [keyframe, {height: '200px'}]);
+  const effect = new KeyframeEffect(null, [keyframe, { height: '200px' }]);
 
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', height: '100px'},
-    {offset: null, computedOffset: 1, easing: 'linear', height: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', height: '100px' },
+    { offset: null, computedOffset: 1, easing: 'linear', height: '200px' },
   ]);
 }, 'Only enumerable properties on keyframes are read');
 
 test(function(t) {
   const KeyframeParent = function() { this.width = '100px'; };
   KeyframeParent.prototype = { height: '100px' };
   const Keyframe = function() { this.top = '100px'; };
   Keyframe.prototype = Object.create(KeyframeParent.prototype);
   Object.defineProperty(Keyframe.prototype, 'left', {
     value: '100px',
-    enumerable: 'true'});
+    enumerable: true,
+  });
   const keyframe = new Keyframe();
 
-  const effect = new KeyframeEffect(null, [keyframe, {top: '200px'}]);
+  const effect = new KeyframeEffect(null, [keyframe, { top: '200px' }]);
 
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', top: '100px'},
-    {offset: null, computedOffset: 1, easing: 'linear', top: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', top: '100px' },
+    { offset: null, computedOffset: 1, easing: 'linear', top: '200px' },
   ]);
 }, 'Only properties defined directly on keyframes are read');
 
 test(function(t) {
   const keyframes = {};
   Object.defineProperty(keyframes, 'width', ['100px', '200px']);
   Object.defineProperty(keyframes, 'height', {
     value: ['100px', '200px'],
-    enumerable: true});
+    enumerable: true,
+  });
 
   const effect = new KeyframeEffect(null, keyframes);
 
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', height: '100px'},
-    {offset: null, computedOffset: 1, easing: 'linear', height: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', height: '100px' },
+    { offset: null, computedOffset: 1, easing: 'linear', height: '200px' },
   ]);
 }, 'Only enumerable properties on property-indexed keyframes are read');
 
 test(function(t) {
   const KeyframesParent = function() { this.width = '100px'; };
   KeyframesParent.prototype = { height: '100px' };
   const Keyframes = function() { this.top = ['100px', '200px']; };
   Keyframes.prototype = Object.create(KeyframesParent.prototype);
   Object.defineProperty(Keyframes.prototype, 'left', {
     value: ['100px', '200px'],
-    enumerable: 'true'});
+    enumerable: true,
+  });
   const keyframes = new Keyframes();
 
   const effect = new KeyframeEffect(null, keyframes);
 
   assert_frame_lists_equal(effect.getKeyframes(), [
-    {offset: null, computedOffset: 0, easing: 'linear', top: '100px'},
-    {offset: null, computedOffset: 1, easing: 'linear', top: '200px'},
+    { offset: null, computedOffset: 0, easing: 'linear', top: '100px' },
+    { offset: null, computedOffset: 1, easing: 'linear', top: '200px' },
   ]);
 }, 'Only properties defined directly on property-indexed keyframes are read');
 
 test(function(t) {
   const expectedOrder = ['composite', 'easing', 'offset', 'left', 'marginLeft'];
   const actualOrder = [];
   const kf1 = {};
   for (const {prop, value} of [{ prop: 'marginLeft', value: '10px' },