Change responsive-test.js neutral keyframe format

third_party/WebKit/LayoutTests/animations/responsive/resources/responsive-test.js

 // Copyright 2015 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.
 
 /*
 Exported function:
 assertResponsive
 
 Call signature:
 assertResponsive({
   property: <CSS Property>,
-  from: ?<CSS Value>,
-  to: ?<CSS Value>,
+  ?from: <CSS Value>,
+  ?to: <CSS Value>,
   configurations: [{
     state: {
       ?underlying: <CSS Value>,
       ?inherited: <CSS Value>,
     },
     expect: [
       { at: <Float>, is: <CSS Value> }
     ],
   }],
 })
@@ skipping 59 matching lines @@
     console.assert(targets.every(function(target) { return target.parentElement === parent; }));
     parent.style[property] = state.inherited;
   }
   if (state.underlying) {
     for (var target of targets) {
       target.style[property] = state.underlying;
     }
   }
 }
 
-function createKeyframes(property, from, to) {
-  return [
-    {[property]: from},
-    {[property]: to},
-  ];
+function keyframeText(options, keyframeName) {
+  return (keyframeName in options) ? `[${options[keyframeName]}]` : 'neutral';
+}
+
+function createKeyframes(options) {
+  var keyframes = [];
+  if ('from' in options) {
+    keyframes.push({
+      offset: 0,
+      [options.property]: options.from,
+    });
+  }
+  if ('to' in options) {
+    keyframes.push({
+      offset: 1,
+      [options.property]: options.to,
+    });
+  }
+  return keyframes;
 }
 
 function startPausedAnimations(targets, keyframes, fractions) {
   console.assert(targets.length == fractions.length);
   for (var i = 0; i < targets.length; i++) {
     var target = targets[i];
     var fraction = fractions[i];
     console.assert(fraction >= 0 && fraction < 1);
     var animation = target.animate(keyframes, 1);
     animation.currentTime = fraction;
     animation.pause();
   }
 }
 
 function runPendingResponsiveTests() {
   var stateTransitionTests = [];
   pendingResponsiveTests.forEach(function(options) {
     var property = options.property;
     var from = options.from;
     var to = options.to;
-    var keyframes = createKeyframes(property, from, to);
+    var keyframes = createKeyframes(options);
+    var fromText = keyframeText(options, 'from');
+    var toText = keyframeText(options, 'to');
 
     var stateTransitions = createStateTransitions(options.configurations);
     stateTransitions.forEach(function(stateTransition) {
       var before = stateTransition.before;
       var after = stateTransition.after;
       var container = createElement('div', document.body);
       var targets = createTargets(after.expect.length, container);
 
       setState(targets, property, before.state);
       startPausedAnimations(targets, keyframes, after.expect.map(function(expectation) { return expectation.at; }));
       stateTransitionTests.push({
         applyStateTransition() {
           setState(targets, property, after.state);
         },
         assert() {
           for (var i = 0; i < targets.length; i++) {
             var target = targets[i];
             var expectation = after.expect[i];
             var actual = getComputedStyle(target)[property];
             test(function() {
               assert_equals(actual, expectation.is);
-            }, `Animation on property <${property}> from [${from}] to [${to}] with ${JSON.stringify(before.state)} changed to ${JSON.stringify(after.state)} at (${expectation.at}) is [${expectation.is}]`);
+            }, `Animation on property <${property}> from ${fromText} to ${toText} with ${JSON.stringify(before.state)} changed to ${JSON.stringify(after.state)} at (${expectation.at}) is [${expectation.is}]`);
           }
         },
       });
     });
   });
 
   // Separate style modification from measurement as different phases to avoid a style recalc storm.
   for (var stateTransitionTest of stateTransitionTests) {
     stateTransitionTest.applyStateTransition();
   }
@@ skipping 18 matching lines @@
   requestAnimationFrame(function() {
     runPendingResponsiveTests();
     asyncHandle.done()
   });
 });
 
 
 window.assertResponsive = assertResponsive;
 
 })();