Use performance.measure api instead of manually tracking with performance.now() (#79)

Author: bgrins

resources/benchmark-runner.mjs

@@ -237,6 +237,7 @@ export class BenchmarkRunner {
 
         const syncTime = syncEndTime - syncStartTime;
 
+        performance.mark(`${suite.name}.${test.name}-async-start`);
         const asyncStartTime = performance.now();
         setTimeout(() => {
             // Some browsers don't immediately update the layout for paint.
@@ -246,6 +247,8 @@ export class BenchmarkRunner {
             const asyncTime = asyncEndTime - asyncStartTime;
             this._frame.contentWindow._unusedHeightValue = height; // Prevent dead code elimination.
             performance.mark(`${suite.name}.${test.name}-async-end`);
+            performance.measure(`${suite.name}.${test.name}-sync`, `${suite.name}.${test.name}-start`, `${suite.name}.${test.name}-sync-end`);
+            performance.measure(`${suite.name}.${test.name}-async`, `${suite.name}.${test.name}-async-start`, `${suite.name}.${test.name}-async-end`);
             window.requestAnimationFrame(() => {
                 callback(syncTime, asyncTime, height);
             });

tests/benchmark-runner-tests.mjs

@@ -211,8 +211,9 @@ describe("BenchmarkRunner", () => {
             it("should write performance marks at the start and end of the test with the correct test name", () => {
                 assert.calledWith(peformanceMarkSpy, "Suite 1.Test 1-start");
                 assert.calledWith(peformanceMarkSpy, "Suite 1.Test 1-sync-end");
+                assert.calledWith(peformanceMarkSpy, "Suite 1.Test 1-async-start");
                 assert.calledWith(peformanceMarkSpy, "Suite 1.Test 1-async-end");
-                assert.calledThrice(peformanceMarkSpy);
+                expect(peformanceMarkSpy.callCount).to.equal(4);
             });
 
             it("should run the test", () => {