Add 'self.onerror' to Worker tests.

LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html

Index: LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html
diff --git a/LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html b/LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html
index b43bcb8af1124d963379df23432dc329b8c08684..84ed3ba71e8577a8b12ff2b300e6e7d6f803f393 100644
--- a/LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html
+++ b/LayoutTests/http/tests/workers/worker-importScripts-onerror-redirect-to-crossorigin.html
@@ -14,6 +14,15 @@
 
         var worker = new Worker('resources/worker-importscripts-onerror-redirect-to-crossorigin.js');
 
+        var workerOnerror;
+        worker.onmessage = function (e) {
+            workerOnerror = e.data;
+            shouldBeEqualToString("workerOnerror.message", "Uncaught undefined");
+            shouldBeEqualToString("workerOnerror.url", "http://127.0.0.1:8000/workers/resources/worker-importscripts-onerror-redirect-to-crossorigin.js");
+            shouldEvaluateTo("workerOnerror.line", 6);
+            shouldEvaluateTo("workerOnerror.column", 0);
+        };
+
         var onerrorMessage, onerrorURL, onerrorLine;
         worker.onerror = function (e) {
             onerrorMessage = e.message;