Use testharness.js instead of js-test.js in LayoutTests/fast/canvas tests.

third_party/WebKit/LayoutTests/fast/canvas/canvas-longlived-context.html

+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script>
+test(function(t) {
 
-<script src="../../resources/js-test.js"></script>
-<script src="canvas-longlived-context.js"></script>
+    var context = document.createElement("canvas").getContext("2d");
+    context.fillStyle = "green";
+    context.fillRect(0,0,100,100);
+    
+    function clobberGC(count) {
+        for (var i = 0; i < 5000; ++i)
+            ({a: i*i*i*0.5+"str", b: i/Math.sqrt(i)});
+        if (count > 0)
+            clobberGC(count-1);
+    }
+    
+    clobberGC(40);
+    assert_array_equals(context.getImageData(50, 50, 1, 1).data, [0, 128, 0, 255]);
+    
+}, 'This test ensures that Canvas and CanvasRenderingContext2D work correctly if the rendering context outlives the canvas element.');
+
+</script>