Add performance tests for full frame cycle

third_party/WebKit/LayoutTests/fast/harness/perftests/measure-time.html

Index: third_party/WebKit/LayoutTests/fast/harness/perftests/measure-time.html
diff --git a/third_party/WebKit/LayoutTests/fast/harness/perftests/measure-time.html b/third_party/WebKit/LayoutTests/fast/harness/perftests/measure-time.html
new file mode 100644
index 0000000000000000000000000000000000000000..00126e290c046ba4df7e805a9c9f07a0decc7135
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/harness/perftests/measure-time.html
@@ -0,0 +1,21 @@
+<script src="../../../../PerformanceTests/resources/runner.js"></script>
+<script>
+// The initial value doesn't affect result.
+var virtualTime = Math.floor(Math.random() * 100000);

[pdr., 2016/10/19 03:50:31]

Nit: could you use a fixed random value like 123456? (here and below)

Your current code isn't flaky but I think it's best to be deterministic when
possible (e.g., easier to debug if it breaks).

[Xianzhu, 2016/10/19 15:17:10]

Done.

+PerfTestRunner.now = function () { return virtualTime; }
+
+var originalSetTimeout = window.setTimeout;
+window.setTimeout = function(f, t) {
+  // This doesn't affect result.
+  virtualTime += Math.floor(Math.random() * 100000);
+  originalSetTimeout(f, t);
+};
+
+PerfTestRunner.measureTime({
+  run: function () {
+    virtualTime += 20;
+  },
+  warmUpCount: 3,
+  doNotMeasureMemoryUsage: true,
+});
+</script>