Handle window.onload and img.onload in image-change-without-resize-shouldnt-layout test.

third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html

Index: third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html
diff --git a/third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html b/third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html
index 8327ff68a5b351be6fec798f97979c9370794445..5f1d904f4bbd66ce8febdd9ff0163af5d69f64a3 100644
--- a/third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html
+++ b/third_party/WebKit/LayoutTests/fast/images/image-change-without-resize-shouldnt-layout.html
@@ -6,11 +6,15 @@
 <img style="max-width: 100%" src="../replaced/resources/1x1-blue.png">
 </div>
 <script>
-//TODO(siva.gunturi): Use async_test and use asserts on image.onload and window.onload.
-test(function() {
-    document.documentElement.offsetTop;
-    var img = document.querySelector("img");
-    img.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAMAAAAoyzS7AAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAAGUExURf8AAAAAAEGjEgMAAAAMSURBVHjaYmAACDAAAAIAAU9tWeEAAAAASUVORK5CYII=";
-    assert_equals(internals.needsLayoutCount(), 0);
+async_test(function(t) {
+    window.onload = t.step_func(function() {
+        document.documentElement.offsetTop;
+        var img = document.querySelector("img");
+        img.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAMAAAAoyzS7AAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAAGUExURf8AAAAAAEGjEgMAAAAMSURBVHjaYmAACDAAAAIAAU9tWeEAAAAASUVORK5CYII=";
+        assert_equals(internals.needsLayoutCount(), 0);
+        img.onload = t.step_func_done(function() {
+            assert_equals(internals.needsLayoutCount(), 0);
+        });
+    });
 });
 </script>