use default performance.measure implementation (#83)

D8 now supports a more web-conformant performance.measure API.
This PR changes the code to use performance.measure directly instead of using the wrapper.

Author: camillobruni

JetStreamDriver.js

@@ -650,7 +650,7 @@ class Benchmark {
                 __benchmark.runIteration();
                 let end = performance.now();
 
-                performanceMeasure(iterationMarkLabel, iterationStartMark);
+                performance.measure(iterationMarkLabel, iterationMarkLabel);
 
                 ${this.postIterationCode}
 
@@ -718,19 +718,11 @@ class Benchmark {
             const isInBrowser = ${isInBrowser};
             const isD8 = ${isD8};
             if (typeof performance.mark === 'undefined') {
-                performance.mark = function() {};
+                performance.mark = function(name) { return { name }};
             }
             if (typeof performance.measure === 'undefined') {
                 performance.measure = function() {};
             }
-            function performanceMeasure(name, mark) {
-                // D8 does not implement the official web API.
-                // Also the performance.mark polyfill returns an undefined mark.
-                if (isD8 || typeof mark === "undefined")
-                    performance.measure(name, mark);
-                else
-                    performance.measure(name, mark.name);
-            }
         `);
 
         if (!!this.plan.deterministicRandom) {
@@ -1181,7 +1173,7 @@ class AsyncBenchmark extends DefaultBenchmark {
                 await __benchmark.runIteration();
                 let end = performance.now();
 
-                performanceMeasure(iterationMarkLabel, iterationStartMark);
+                performance.measure(iterationMarkLabel, iterationMarkLabel);
 
                 ${this.postIterationCode}
 
@@ -1280,7 +1272,7 @@ class WSLBenchmark extends Benchmark {
                 benchmark.buildStdlib();
                 results.push(performance.now() - start);
 
-                performanceMeasure(markLabel, startMark);
+                performance.measure(markLabel, markLabel);
             }
 
             {
@@ -1291,7 +1283,7 @@ class WSLBenchmark extends Benchmark {
                 benchmark.run();
                 results.push(performance.now() - start);
 
-                performanceMeasure(markLabel, startMark);
+                performance.measure(markLabel, markLabel);
             }
 
             top.currentResolve(results);