Refactor prepareToMeasureValuesAsync to startMeasureValuesAsyn which run test through callback

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

Index: third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js
diff --git a/third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js b/third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js
index 21c3fe11d5bf7597517a68c9d009a5bb17787b3d..7903f73c990bacad75c21c9582e2fac49b1f4d80 100644
--- a/third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js
+++ b/third_party/WebKit/PerformanceTests/Canvas/resources/canvas_runner.js
@@ -9,14 +9,18 @@
     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() {