Refactor prepareToMeasureValuesAsync to startMeasureValuesAsyn which run test through callback

third_party/WebKit/PerformanceTests/resources/runner.js

 // There are tests for computeStatistics() located in LayoutTests/fast/harness/perftests
 
 if (window.testRunner) {
     testRunner.waitUntilDone();
     testRunner.dumpAsText();
 }
 
 (function () {
     var logLines = null;
     var completedIterations = -1;
@@ skipping 127 matching lines @@
 
     PerfTestRunner.forceLayout = function(doc) {
         doc = doc || document;
         if (doc.body)
             doc.body.offsetHeight;
         else if (doc.documentElement)
             doc.documentElement.offsetHeight;
     };
 
     function start(test, scheduler, runner) {
-        if (!test) {
+        if (!test || !runner) {
             PerfTestRunner.logFatalError("Got a bad test object.");
             return;
         }
         currentTest = test;
 
         if (test.tracingCategories && !test.traceEventsToMeasure) {
             PerfTestRunner.logFatalError("test's tracingCategories is " +
                 "specified but test's traceEventsToMeasure is empty");
             return;
         }
 
         if (test.traceEventsToMeasure && !test.tracingCategories) {
             PerfTestRunner.logFatalError("test's traceEventsToMeasure is " +
                 "specified but test's tracingCategories is empty");
             return;
         }
         iterationCount = test.iterationCount || (window.testRunner ? 5 : 20);
         if (test.warmUpCount && test.warmUpCount > 0)
             completedIterations = -test.warmUpCount;
         logLines = PerfTestRunner.bufferedLog || window.testRunner ? [] : null;
         PerfTestRunner.log("Running " + iterationCount + " times");
         if (test.doNotIgnoreInitialRun)
             completedIterations++;
 
-        if (runner && test.tracingCategories && window.testRunner &&
-            window.testRunner.supportTracing) {
-            window.testRunner.startTracing(test.tracingCategories, function() {
+        if (!test.tracingCategories) {
+            scheduleNextRun(scheduler, runner);
+            return;
+        }
+
+        if (window.testRunner && window.testRunner.supportTracing) {
+            testRunner.startTracing(test.tracingCategories, function() {
                 scheduleNextRun(scheduler, runner);
             });
-        } else if (runner) {
-            if (test.tracingCategories && !(window.testRuner &&
-                  window.testRunner.supportTracing)) {
-                PerfTestRunner.log("Tracing based metrics are specified but " +
-                    "tracing is not supported on this platform. To get those " +
-                    "metrics from this test, you can run the test using " +
-                    "tools/perf/run_benchmarks script.");
-            }
-            scheduleNextRun(scheduler, runner);
+            return;
         }
+
+        PerfTestRunner.log("Tracing based metrics are specified but " +
+            "tracing is not supported on this platform. To get those " +
+            "metrics from this test, you can run the test using " +
+            "tools/perf/run_benchmarks script.");
+        scheduleNextRun(scheduler, runner);
     }
 
     function scheduleNextRun(scheduler, runner) {
+        if (!scheduler) {
+          // This is an async measurement test which has its own scheduler.
+          try {

[Xianzhu, 2017/05/03 22:06:26]

Nit: Use indentation same as the reset of this file.

[nednguyen, 2017/05/04 00:10:32]

Done.

+            runner();
+          } catch (exception) {
+            PerfTestRunner.logFatalError("Got an exception while running test.run with name=" + exception.name + ", message=" + exception.message);
+          }
+          return;
+        }

[Xianzhu, 2017/05/03 22:06:26]

Nit: insert a blank line after this line.

[nednguyen, 2017/05/04 00:10:33]

Done.

         scheduler(function () {
             // This will be used by tools/perf/benchmarks/blink_perf.py to find
             // traces during the measured runs.
             if (completedIterations >= 0)
                 console.time("blink_perf");
 
             try {
                 if (currentTest.setup)
                     currentTest.setup();
 
@@ skipping 56 matching lines @@
                 testRunner.stopTracingAndMeasure(
                     currentTest.traceEventsToMeasure, function() {
                         testRunner.notifyDone();
                     });
             } else {
                 testRunner.notifyDone();
             }
         }
     }
 
     PerfTestRunner.prepareToMeasureValuesAsync = function (test) {

[Xianzhu, 2017/05/03 22:06:26]

As test.run is called inside of this function, it no longer just "prepare".

"startMeasureValuesAsync"?

[nednguyen, 2017/05/04 00:10:50]

Done.

         PerfTestRunner.unit = test.unit;
-        start(test);
+        start(test, undefined, function() { test.run() });
     }
 
     PerfTestRunner.measureValueAsync = function (measuredValue) {
         completedIterations++;
 
         try {
             ignoreWarmUpAndLog(measuredValue);
         } catch (exception) {
             PerfTestRunner.logFatalError("Got an exception while logging the result with name=" + exception.name + ", message=" + exception.message);
             return;
@@ skipping 146 matching lines @@
 
             iframe.contentDocument.close();
             document.body.removeChild(iframe);
         };
 
         PerfTestRunner.measureTime(test);
     }
 
     window.PerfTestRunner = PerfTestRunner;
 })();