Refactor prepareToMeasureValuesAsync to startMeasureValuesAsyn which run test through callback

third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js

 // CanvasRunner is a wrapper of PerformanceTests/resources/runner.js for canvas tests.
 (function () {
     var MEASURE_DRAW_TIMES = 50;
     var MAX_MEASURE_DRAW_TIMES = 1000;
     var MAX_MEASURE_TIME_PER_FRAME = 1000; // 1 sec
     var currentTest = null;
     var isTestDone = false;
 
     var CanvasRunner = {};
 
     CanvasRunner.start = function (test) {
-        PerfTestRunner.prepareToMeasureValuesAsync({unit: 'runs/s',
-            description: test.description, done: testDone});
-        if (!test.doRun) {
-            CanvasRunner.logFatalError("doRun must be set.");
-            return;
-        }
-        currentTest = test;
-        runTest();
+        PerfTestRunner.prepareToMeasureValuesAsync({
+            unit: 'runs/s',
+            description: test.description,
+            done: testDone,
+            run: function() {
+                if (!test.doRun) {
+                    CanvasRunner.logFatalError("doRun must be set.");
+                    return;
+                }
+                currentTest = test;
+                runTest();
+            }});
     }
 
     function runTest() {
         try {
             if (currentTest.preRun)
                 currentTest.preRun();
 
             var start = PerfTestRunner.now();
             var count = 0;
             while ((PerfTestRunner.now() - start <= MAX_MEASURE_TIME_PER_FRAME) && (count * MEASURE_DRAW_TIMES < MAX_MEASURE_DRAW_TIMES)) {
@@ skipping 55 matching lines @@
         };
 
         video.addEventListener('playing', playingListener, true);
         video.addEventListener('timeupdate', timeupdateListener, true);
         video.loop = true;
         video.play();
     }
 
     window.CanvasRunner = CanvasRunner;
 })();