This issue was originally filed by matt...@chromium.org

What steps will reproduce the problem?
1.In a dart application, attempt to access a CORs enabled page on a seperate domain

Future<HttpRequest> request = HttpRequest.request(
       'http://labs.gauntface.co.uk/eisandnose/demofeed.rss'
      );
request.then((request) {
    if (request.readyState == HttpRequest.DONE &&
        (request.status == 200)) {
        onSuccess(request.responseText);
    } else if (request.readyState == HttpRequest.DONE) {
      onError(msg: 'An unknown error occured. Please try again.');
    }
  });
request.catchError((error) {
    print('catchError() value = error');
    onError();
});

2.Notice the following error message in the console:

XMLHttpRequest cannot load http://labs.gauntface.co.uk/eisandnose/demofeed.rss. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:3030' is therefore not allowed access.

What is the expected output? What do you see instead?
The request should go through without any issues.

If you load the URL 'http://labs.gauntface.co.uk/eisandnose/demofeed.rss' in Desktop Chrome (Not Dartium) you'll see that the headers include 'Access-Control-Allow-Origin:' in the Network tab (also shows in curl -v 'http://labs.gauntface.co.uk/eisandnose/demofeed.rss'). However loading the page directly in Dartium and looking in the network tab in DevTools, the 'Access-Control-Allow-Origin:' isn't shown.

What version of the product are you using? On what operating system?
Version 31.0.1650.39 (1593)

Please provide any additional information below.
If anyone is desperate for a way around this , you can add '--disable-web-security' in the run command of the Dart Editor, but you obviously won't be able to deploy this anywhere and runs some risks