[HTMLCanvasElement.toBlob] Default callback version without scheduler

LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html

Index: LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html
diff --git a/LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html b/LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html
index 592f408fbfd93589b94f9a63bad0e23d89b5b799..81ca5710cc2ed9418be61b1fa533181cf13ba595 100644
--- a/LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html
+++ b/LayoutTests/http/tests/security/canvas-read-blocked-by-setting.html
@@ -49,4 +49,14 @@ test(function () {
             assert_unreached('toDataURL should throw');
         });
 }, 'toDataURL');
+
+test(function () {
+    assert_throws(
+        "SecurityError",
+        function() {
+            context.drawImage(image, 0, 0, 100, 100);
+            canvas.toBlob(function(blob){});
+            assert_unreached('toBlob should throw');
+        });
+}, 'toBlob');
 </script>