Switch IndexedDB1Test to use addEventListener.

tools/testing/dart/browser_test.dart

Index: tools/testing/dart/browser_test.dart
diff --git a/tools/testing/dart/browser_test.dart b/tools/testing/dart/browser_test.dart
index 552a7b998c5166052018e26b4ec09b2723220a80..7449dd1cee58a914e7cf6e02dfd5c8dfd668f705 100644
--- a/tools/testing/dart/browser_test.dart
+++ b/tools/testing/dart/browser_test.dart
@@ -23,7 +23,11 @@ String GetHtmlContents(String title,
   <script type="text/javascript" src="$controllerScript"></script>
   <script type="text/javascript">
     // If nobody intercepts the error, finish the test.
-    onerror = function() { window.layoutTestController.notifyDone() };
+    onerror = function(message, url, lineNumber) {
+       if (window.layoutTestController) {
+         window.layoutTestController.notifyDone();
+       }
+    };
 
     document.onreadystatechange = function() {
       if (document.readyState != "loaded") return;