Fix end_to_end_test to not hang in CSP mode.

dart/tests/try/end_to_end_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Whitebox integration/end-to-end test of Try Dart! site.
 ///
 /// This test opens Try Dart! in an iframe.  When opened the first time, Try
 /// Dart! will display a simple hello-world example, color tokens, compile the
 /// example, and run the result.  We've instrumented Try Dart! to use
 /// window.parent.postMessage when the running program prints anything. So this
 /// test just waits for a "Hello, World!" message.
 library trydart.end_to_end_test;
 
 import 'dart:html';
 import 'dart:async';
 
 // TODO(ahe): Remove this import if issue 17936 is fixed.
 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;
   });
 }
 
 void installErrorHandlerOn(IFrameElement iframe) {
   // This method uses dart:js to install an error event handler on the content
   // window of [iframe]. This is a workaround for http://dartbug.com/17936.
   var iframeProxy = new hack.JsObject.fromBrowserObject(iframe);
   var contentWindowProxy = iframeProxy['contentWindow'];
   if (contentWindowProxy == null) {
     print('No contentWindow in iframe');
     throw 'No contentWindow in iframe';
   }
-  contentWindowProxy.callMethod('addEventListener', ['error', (eventProxy) {
-    onError(
-        eventProxy['message'], eventProxy['filename'], eventProxy['lineno']);
-  }]);
   contentWindowProxy['onerror'] = onError;
+
+  // Note: we have two options, use "iframe.contentWindow.onerror = ..." or

[ricow1, 2014/05/08 05:33:10]

move this comment above the code line doing it?

+  // "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).
 }
 
 void onIframeLoaded(Event event) {
   installErrorHandlerOn(event.target);
 }
 
 void main() {
   asyncStart();
   window.onMessage.listen((MessageEvent e) {
     if (e.data == 'Hello, World!\n') {
       // Clear the DOM to work around a bug in test.dart.
       document.body.nodes.clear();
 
       // Clean up after ourselves.
       window.localStorage.clear();
 
-      asyncSuccess(null);
-    } else {
-      window.console.dir(e.data);
+      asyncEnd();
     }
   });
 
   // Clearing localStorage makes Try Dart! think it is opening for the first
   // time.
   window.localStorage.clear();
 
   IFrameElement iframe = new IFrameElement()
+      ..src = '/root_build/try_dartlang_org/index.html'
       ..style.width = '90vw'
       ..style.height = '90vh'
       ..onLoad.listen(onIframeLoaded);
   document.body.append(iframe);
   // Install an error handler both on the new iframe element, and when it has
   // 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';
 }