Don't expose the user agent shadow tree

LayoutTests/svg/custom/use-event-handler-on-referenced-element-hierarchy.svg

-<svg version="1.1" baseProfile="basic" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" onload="runRepaintAndPixelTest()">
+<svg version="1.1" baseProfile="basic" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" onload="clickRect()">
   <script xlink:href="../../fast/repaint/resources/text-based-repaint.js"/>
   <defs>
-   <rect id="reference" x="240" y="1" width="239" height="358"/>
+    <g id="reference">
+      <rect onclick="test(evt)" id="referenceRect" x="240" y="1" width="239" height="358"/>
+    </g>
 
    <script type="text/ecmascript">
     <![CDATA[
-    window.outputRepaintRects = false;
-    function repaintTest() {
+    if (window.testRunner)
+        testRunner.dumpAsText();
+
+    function clickRect() {
         if (window.eventSender) {
             testRunner.waitUntilDone();
             eventSender.mouseMoveTo(250, 50);
             eventSender.mouseDown();
             eventSender.mouseUp();
         }
     }
 
-    function test() {
-        document.getElementById("text").firstChild.nodeValue = "Test passed.";
+    function test(evt) {
+        var rect = evt.currentTarget;
+        if (rect.parentNode == "[object SVGGElement]" && rect.parentNode.parentNode == "[object SVGDefsElement]")

[esprehn, 2014/06/12 21:52:36]

Can you compare to a real node in the page? getElementById something and then do
== instead of string checks.

+            document.getElementById("text").firstChild.nodeValue = "Test passed.";
         if (window.testRunner)
             testRunner.notifyDone();
     }
     ]]>
     </script>
   </defs>
 
-  <use id="use" onclick="test()" xlink:href="#reference" fill="grey"/>
+  <use xlink:href="#reference" fill="grey"/>
 
   <text id="text" transform="translate(5,20)">Test failed.</text>
   <rect id="test-frame" x="1" y="1" width="478" height="358" fill="none" stroke="#000"/>
 </svg>