Convert some pixel tests in fast/canvas into ref tests.

LayoutTests/fast/canvas/font-update-expected.html

Index: LayoutTests/fast/canvas/font-update-expected.html
diff --git a/LayoutTests/fast/canvas/font-update.html b/LayoutTests/fast/canvas/font-update-expected.html
similarity index 51%
copy from LayoutTests/fast/canvas/font-update.html
copy to LayoutTests/fast/canvas/font-update-expected.html
index 6b93a95103f19ac144629dc17534f0b14d41bc51..831ad8279af9d2d78cf4e87adfe71f7e7a5f081d 100644
--- a/LayoutTests/fast/canvas/font-update.html
+++ b/LayoutTests/fast/canvas/font-update-expected.html
@@ -12,16 +12,5 @@
     ctx.fillStyle = "red";
     ctx.fillText("B", 0, 100);
     ctx.fillStyle = "green";
-    canvas.parentNode.removeChild(canvas);
-    if (window.testRunner) {
-        testRunner.dumpAsTextWithPixelResults();
-        testRunner.waitUntilDone();
-	}
-    setTimeout(function()
-    {
-        ctx.fillText("A", 0, 100);
-        document.body.appendChild(canvas);
-        if (window.testRunner)
-            testRunner.notifyDone();
-    }, 50);
+    ctx.fillText("A", 0, 100);
 </script>