diff -r 000000000000 -r 6474c204b198 layout/reftests/scrolling/scrolling.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/reftests/scrolling/scrolling.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+var topElements = document.getElementsByClassName("scrollTop");
+if (!topElements.length) {
+  topElements = [document.documentElement];
+}
+
+var failed = false;
+
+function doScroll(d)
+{
+  if (failed)
+    return;
+  for (var i = 0; i < topElements.length; ++i) {
+    var e = topElements[i];
+    e.scrollTop = d;
+    if (e.scrollTop != d) {
+      document.documentElement.textContent =
+          "Scrolling failed on " + e.tagName + " element, " +
+          "tried to scroll to " + d + ", got " + e.scrollTop +
+          " (Random number: " + Math.random() + ")";
+      failed = true;
+    }
+  }
+}
+
+if (document.location.search == '?ref') {
+  doScroll(20);
+} else if (document.location.search == '?up') {
+  doScroll(40);
+  document.documentElement.setAttribute("class", "reftest-wait");
+  window.addEventListener("MozReftestInvalidate", function() {
+    document.documentElement.removeAttribute("class");
+    doScroll(20);
+  }, false);
+} else {
+  doScroll(1);
+  document.documentElement.setAttribute("class", "reftest-wait");
+  window.addEventListener("MozReftestInvalidate", function() {
+    document.documentElement.removeAttribute("class");
+    doScroll(20);
+  }, false);
+}