Make reftests work for sky.

sky/tests/harness/reftest-mismatch-expected-mismatch.sky

Index: sky/tests/harness/reftest-mismatch-expected-mismatch.sky
diff --git a/sky/tests/harness/reftest-mismatch-expected-mismatch.sky b/sky/tests/harness/reftest-mismatch-expected-mismatch.sky
new file mode 100644
index 0000000000000000000000000000000000000000..25e46f88ac019e580766e1026a7c26bcd2cae3b5
--- /dev/null
+++ b/sky/tests/harness/reftest-mismatch-expected-mismatch.sky
@@ -0,0 +1,12 @@
+<foo>
+This is a mismatch reftest.
+<script>
+window.addEventListener('load', function() {
+    // TODO(ojan): requestAnimationFrame once we properly pump frames.
+    // https://github.com/domokit/mojo/issues/32
+    setTimeout(function() {
+        internals.notifyTestComplete("");
+    }, 100);
+})
+</script>
+</foo>