Fix fake mouse move event on scroll

LayoutTests/fast/events/overflow-scroll-fake-mouse-move.html

 <div id="target" style="overflow: auto; height: 200px; width: 200px;">
     <div onmouseover="mouseOver(event)" style="margin: 300px 0; width: 100px; height: 100px; background-color: blue;"></div>
 </div>
-<div id="result">Test did not run</div>
+<div id="result">Test needs DumpRenderTree</div>
 <script>
-    var passed = false;
-
     function mouseOver(event)
     {
-        passed = true;
-    }
-
-    function finish()
-    {
-        document.getElementById("result").innerText = passed ? "PASS" : "FAIL";
+        document.getElementById("result").innerText = "PASS";
         testRunner.notifyDone();
     }
 
     if (window.testRunner) {
         testRunner.dumpAsText();
         testRunner.waitUntilDone();
 
-        // WebKit schedules a fake mouse move event as part of installing the WebView in
-        // a window. For the test to be valid, it must begin only after that event
-        // gets dispatched.
-        setTimeout(function()
+        onload = function()
         {
             eventSender.mouseMoveTo(50, 100);
             document.getElementById("target").scrollTop = 250;
-            setTimeout(finish, 200);
-        }, 200);
+        };
     }
 </script>