Fix end_to_end_test to not hang in CSP mode.

dart/tests/try/end_to_end_test.dart

Index: dart/tests/try/end_to_end_test.dart
diff --git a/dart/tests/try/end_to_end_test.dart b/dart/tests/try/end_to_end_test.dart
index 3452aa8c39b4e73fbd4f3dea79143ae7cd2721d5..ae2d14e85f1d59cab1fc2a5a7f2084a8aadb1a51 100644
--- a/dart/tests/try/end_to_end_test.dart
+++ b/dart/tests/try/end_to_end_test.dart
@@ -19,15 +19,31 @@ import 'dart:js' as hack;
 
 import 'package:async_helper/async_helper.dart';
 
-void onError(String message, String filename, int lineno) {
-  if (filename != null) {
-    message = '$filename:$lineno: $message';
+void onError(String message, String filename, int lineno, [int colno, error]) {
+  if (filename != null && filename != "" && lineno != 0) {
+    if (colno != null && colno != 0) {
+      message = '$filename:$lineno:$colno $message';
+    } else {
+      message = '$filename:$lineno: $message';
+    }
   }
-  print("Error occurred in Try Dart iframe: $message");
+  if (error != null) {
+    // See:
+    // https://mikewest.org/2013/08/debugging-runtime-errors-with-window-onerror
+    var stack = error['stack'];
+    if (stack != null) {
+      message += '\n$stack';
+    }
+  }
+  message = "Error occurred in Try Dart iframe: $message";
+
+  // Synchronous, easier to read when running the browser manually.
+  window.console.log(message);
+
   new Future(() {
-    // Chrome seems to not call window.onerror when you throw in response to an
-    // error event.  So we throw the error in a future.
-    throw 'Error from iframe: $message';
+    // Browsers ignore errors throw in event listeners (or from
+    // window.onerror).
+    throw message;
   });
 }
 
@@ -40,10 +56,11 @@ void installErrorHandlerOn(IFrameElement iframe) {
     print('No contentWindow in iframe');
     throw 'No contentWindow in iframe';
   }
-  contentWindowProxy.callMethod('addEventListener', ['error', (eventProxy) {
-    onError(
-        eventProxy['message'], eventProxy['filename'], eventProxy['lineno']);
-  }]);
+
+  // Note: we have two options, use "iframe.contentWindow.onerror = ..." or
+  // "iframe.contentWindow.addEventListener('error', ...)".  The former seems
+  // to provide more details on both Chrome and Firefox (which provides no
+  // information at all in error events).
   contentWindowProxy['onerror'] = onError;
 }
 
@@ -61,9 +78,7 @@ void main() {
       // Clean up after ourselves.
       window.localStorage.clear();
 
-      asyncSuccess(null);
-    } else {
-      window.console.dir(e.data);
+      asyncEnd();
     }
   });
 
@@ -72,6 +87,7 @@ void main() {
   window.localStorage.clear();
 
   IFrameElement iframe = new IFrameElement()
+      ..src = '/root_build/try_dartlang_org/index.html'
       ..style.width = '90vw'
       ..style.height = '90vh'
       ..onLoad.listen(onIframeLoaded);
@@ -80,6 +96,4 @@ void main() {
   // fired the load event.  That seems to matter according to some sources on
   // stackoverflow.
   installErrorHandlerOn(iframe);
-
-  iframe.src = '/root_build/try_dartlang_org/index.html';
 }