Remove support for the externalResourcesRequired attribute.

LayoutTests/svg/custom/svg2-loadevents-normal.svg

Index: LayoutTests/svg/custom/svg2-loadevents-normal.svg
diff --git a/LayoutTests/svg/custom/loadevents-normal-displaynone.svg b/LayoutTests/svg/custom/svg2-loadevents-normal.svg
similarity index 66%
rename from LayoutTests/svg/custom/loadevents-normal-displaynone.svg
rename to LayoutTests/svg/custom/svg2-loadevents-normal.svg
index 75f5b555c93aa7f7c4c483502e501861b069dc42..fd90359c55bf9ea818311cbc73dd818fa4db9cb5 100644
--- a/LayoutTests/svg/custom/loadevents-normal-displaynone.svg
+++ b/LayoutTests/svg/custom/svg2-loadevents-normal.svg
@@ -12,9 +12,8 @@
       function runTest()
       {
         var test = document.getElementById("console");
-        if ( results.length != 4 || results[0] != "image" ||
-             results[1] != "text" || results[2] != "g" ||
-             results[3] != "svg") {
+        if ( results.length != 2 || results[0] != "image" ||
+             results[1] != "svg") {
           test.appendChild(document.createTextNode("Failed"));
         } else {
           test.appendChild(document.createTextNode("Passed"));
@@ -23,8 +22,8 @@
     ]]>
   </script>
   <g onload="reportLoadEvent(this)">
-    <image display="none" externalResourcesRequired="false" id="image" onload="reportLoadEvent(this)" width="100" height="100" xlink:href="resources/green-checker.png" />
-    <text y="130" x="20">This tests normal load dispatching order and an image that does not render(display=none). Bug 16447</text>
+    <image id="image" onload="reportLoadEvent(this)" width="100" height="100" xlink:href="resources/green-checker.png" />
+    <text y="130" x="20">This tests normal load dispatching order.</text>
     <text y="150" x="20" id="console" onload="reportLoadEvent(this)"/>
   </g>
 </svg>