Revert "Polymer elements added to third_party/polymer."

third_party/polymer/components/web-animations-js/test/testcases/auto-test-keyframe-easing.html

-<style>
-#container {
-  position: relative;
-}
-
-#control {
-  position: absolute;
-  background-color: black;
-  width: 20px;
-  height: 0px;
-}
-
-#target {
-  position: absolute;
-  left: 20px;
-  background-color: rgba(0, 128, 0, 0.25);
-  width: 280px;
-  height: 0px;
-}
-
-.block {
-  padding-left: 30px;
-  border-bottom: 1px solid black;
-  box-sizing: border-box;
-  width: 300px;
-  height: 50px;
-  font-size: 20px;
-}
-</style>
-
-<div id="container">
-  <div id="control"></div>
-  <div id="target"></div>
-</div>
-<script src="../bootstrap.js"></script>
-<script>
-var easings = [
-  '',
-  'linear',
-  'ease-in-out',
-  'step-middle',
-  'steps(4, end)',
-];
-
-var keyframeHeight = 50;
-var timing = {duration: easings.length * 1000, fill: 'forwards'};
-
-control.animate({height: easings.length * keyframeHeight + 'px'}, timing);
-
-var keyframes = [];
-easings.forEach(function (easing, i) {
-  var textBlock = document.createElement('div');
-  textBlock.textContent = easing.length ? easing : '<default>';
-  textBlock.classList.add('block');
-  container.appendChild(textBlock);
-  var keyframe = {height: i * keyframeHeight + 'px'};
-  if (easing.length) {
-    keyframe.easing = easing;
-  }
-  keyframes.push(keyframe);
-});
-keyframes.push({height: easings.length * keyframeHeight + 'px'});
-target.animate(keyframes, timing);
-</script>