Add perf tests for animations using different CSS value types

tools/perf/page_sets/tough_animation_cases/resources/css_value_type.js

Index: tools/perf/page_sets/tough_animation_cases/resources/css_value_type.js
diff --git a/tools/perf/page_sets/tough_animation_cases/resources/css_value_type.js b/tools/perf/page_sets/tough_animation_cases/resources/css_value_type.js
new file mode 100644
index 0000000000000000000000000000000000000000..f33654df2869dd0895b9a708fd8a4176ba01571e
--- /dev/null
+++ b/tools/perf/page_sets/tough_animation_cases/resources/css_value_type.js
@@ -0,0 +1,56 @@
+// 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.
+'use strict';
+
+function perfTestCSSValue(options) {
+  var property = options.property;
+  var from = options.from;
+  var to = options.to;
+  console.assert(property);
+  console.assert(from);
+  console.assert(to);
+  console.assert(PerfTestHelper);
+  console.assert(document.getElementById('container'));

[sullivan, 2015/02/17 14:30:31]

Are these left in intentionally because they make it easier to debug when
something goes wrong?

[alancutter (OOO until 2018), 2015/02/17 20:42:12]

Yes. There are a couple of preconditions to this script and I think asserts are
the simplest way to document and enforce them.

+
+  var duration = 15000;
+
+  var N = PerfTestHelper.getN(1000);
+  var targets = [];
+  for (var i = 0; i < N; i++) {
+    var target = document.createElement('target');
+    targets.push(target);
+    container.appendChild(target);
+  }
+
+  var api = PerfTestHelper.getParameter('api');
+  switch (api) {
+  case 'css_animations':
+    var style = document.createElement('style');
+    style.textContent = '' +
+      '@-webkit-keyframes anim {\n' +
+      '  from {' + property + ': ' + from + ';}\n' +
+      '  to {' + property + ': ' + to + ';}\n' +
+      '}\n' +
+      'target {\n' +
+      '  -webkit-animation: anim ' + duration + 'ms linear infinite;\n' +
+      '}\n';
+    document.head.appendChild(style);
+    break;
+  case 'web_animations':
+    var keyframes = [{}, {}];
+    keyframes[0][property] = from;
+    keyframes[1][property] = to;
+    targets.forEach(function(target) {
+      target.animate(keyframes, {
+        duration: duration,
+        iterations: Infinity,
+      });
+    });
+    break;
+  default:
+    throw 'Invalid api: ' + api;
+  }
+
+  PerfTestHelper.signalReady();
+}