Enable blink_perf.canvas on Android Perf bots

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("\ndoRun must be set.\n");
+            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)) {
                 for (var i = 0; i < MEASURE_DRAW_TIMES; i++) {
                     currentTest.doRun();
                 }
                 count++;
             }
             if (currentTest.ensureComplete)
                 currentTest.ensureComplete();
             var elapsedTime = PerfTestRunner.now() - start;
             if (currentTest.postRun)
                 currentTest.postRun();
 
             PerfTestRunner.measureValueAsync(MEASURE_DRAW_TIMES * count * 1000 / elapsedTime);
         } catch(err) {
-            CanvasRunner.logFatalError("\ntest fails due to GPU issue. " + err + "\n");
+            CanvasRunner.logFatalError("test fails due to GPU issue. " + err);
             return;
         }
 
         if (!isTestDone)
             requestAnimationFrame(runTest);
     }
 
     function testDone() {
         isTestDone = true;
     }
 
     CanvasRunner.logFatalError = function (text) {
         PerfTestRunner.logFatalError(text);
     }
 
+    CanvasRunner.startPlayingAndWaitForVideo = function (video, callback) {
+        var gotPlaying = false;
+        var gotTimeUpdate = false;
+
+        var maybeCallCallback = function() {
+            if (gotPlaying && gotTimeUpdate && callback) {
+                callback(video);
+                callback = undefined;
+                video.removeEventListener('playing', playingListener, true);
+                video.removeEventListener('timeupdate', timeupdateListener, true);
+            }
+        };
+
+        var playingListener = function() {
+            gotPlaying = true;
+            maybeCallCallback();
+        };
+
+        var timeupdateListener = function() {
+            // Checking to make sure the current time has advanced beyond
+            // the start time seems to be a reliable heuristic that the
+            // video element has data that can be consumed.
+            if (video.currentTime > 0.0) {
+                gotTimeUpdate = true;
+                maybeCallCallback();
+            }
+        };
+
+        video.addEventListener('playing', playingListener, true);
+        video.addEventListener('timeupdate', timeupdateListener, true);
+        video.loop = true;
+        video.play();
+    }
+
     window.CanvasRunner = CanvasRunner;
 })();