[DevTools] New harness for inspector-protocol layout tests

third_party/WebKit/LayoutTests/inspector-protocol/animation/animation-empty-transition-cancel.js

+(async function() {
+  let {page, session, Protocol} = await InspectorTest.startHTML(`
+    <div id='node' style='background-color: red; width: 100px'></div>
+  `, '');
+
+  Protocol.Animation.onAnimationCreated(() => InspectorTest.log('Animation created'));
+  Protocol.Animation.onAnimationCanceled(() => InspectorTest.log('Animation canceled'));
+  Protocol.Animation.enable();
+  await session.evaluate(`
+    node.offsetTop;
+    node.style.transition = "1s";
+    node.offsetTop;
+    node.style.width = "200px";
+    node.offsetTop;
+    node.style.transition = "";
+    node.offsetTop;
+  `);
+  InspectorTest.completeTest();
+})();