Refactor prepareToMeasureValuesAsync to startMeasureValuesAsyn which run test through callback

third_party/WebKit/PerformanceTests/resources/runner.js

Index: third_party/WebKit/PerformanceTests/resources/runner.js
diff --git a/third_party/WebKit/PerformanceTests/resources/runner.js b/third_party/WebKit/PerformanceTests/resources/runner.js
index 246385aec10c297d876244d3f14ab21bdcda51f9..9cca63b32a4bf938950430157a2f1560c0b10b77 100644
--- a/third_party/WebKit/PerformanceTests/resources/runner.js
+++ b/third_party/WebKit/PerformanceTests/resources/runner.js
@@ -145,7 +145,7 @@ if (window.testRunner) {
     };
 
     function start(test, scheduler, runner) {
-        if (!test) {
+        if (!test || !runner) {
             PerfTestRunner.logFatalError("Got a bad test object.");
             return;
         }
@@ -170,24 +170,35 @@ if (window.testRunner) {
         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.
@@ -266,7 +277,7 @@ if (window.testRunner) {
 
     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) {