Authentication works in Dartium, but not when compiled with dart2js

[terrasea]

I'm putting it here first, to see if it's a problem with the library itself, but I suspect it's a overall Dart2JS problem.

I should be seeing a separate widow prompting me to login if I've not already, followed by a OAuth app permission request. This works when I run it in Dartium, but when I use

pub serve

executing it in Google Chrome.

What I get instead is:

Uncaught Error: NullError: Cannot call "closed" on null js_primitives.dart:25
Stack Trace: 
TypeError: Cannot read property 'closed' of undefined
    at _DOMWindowCrossFrame.get$closed (http://localhost:8080/index.dart.js:7527:32)
    at dart.J.get$closed$x (http://localhost:8080/index.dart.js:8807:39)
    at _WindowPoller.poll$0 (http://localhost:8080/index.dart.js:8425:13)
    at GoogleOAuth2_login_completeByPromptingUser_closure.call$1 (http://localhost:8080/index.dart.js:8126:56)
    at dart._rootRunUnary (http://localhost:8080/index.dart.js:3249:16)
    at _Future__propagateToListeners_handleValueCallback.call$0 (http://localhost:8080/index.dart.js:3627:47)
    at dart._Future.static._Future__propagateToListeners (http://localhost:8080/index.dart.js:3531:131)
    at _Future._completeWithValue$1 (http://localhost:8080/index.dart.js:3390:9)
    at _Future__asyncComplete_closure0.call$0 (http://localhost:8080/index.dart.js:3609:19)
    at _AsyncCallbackEntry.callback$0 (http://localhost:8080/index.dart.js:3769:28)
 js_primitives.dart:25
microtask error TypeError: Cannot read property 'closed' of undefined
    at _DOMWindowCrossFrame.get$closed (http://localhost:8080/index.dart.js:7527:32)
    at dart.J.get$closed$x (http://localhost:8080/index.dart.js:8807:39)
    at _WindowPoller.poll$0 (http://localhost:8080/index.dart.js:8425:13)
    at GoogleOAuth2_login_completeByPromptingUser_closure.call$1 (http://localhost:8080/index.dart.js:8126:56)
    at dart._rootRunUnary (http://localhost:8080/index.dart.js:3249:16)
    at _Future__propagateToListeners_handleValueCallback.call$0 (http://localhost:8080/index.dart.js:3627:47)
    at dart._Future.static._Future__propagateToListeners (http://localhost:8080/index.dart.js:3531:131)
    at _Future._completeWithValue$1 (http://localhost:8080/index.dart.js:3390:9)
    at _Future__asyncComplete_closure0.call$0 (http://localhost:8080/index.dart.js:3609:19)
    at _AsyncCallbackEntry.callback$0 (http://localhost:8080/index.dart.js:3769:28) js_primitives.dart:25
microtask error stack trace: Error
    at dart.wrapException (http://localhost:8080/index.dart.js:1835:15)
    at _rootHandleUncaughtError__closure.call$0 (http://localhost:8080/index.dart.js:3995:15)
    at _AsyncCallbackEntry.callback$0 (http://localhost:8080/index.dart.js:3769:28)
    at dart._asyncRunCallbackLoop (http://localhost:8080/index.dart.js:3152:13)
    at _asyncRunCallback (http://localhost:8080/index.dart.js:3161:9)
    at TimerImpl_internalCallback0.call$0 (http://localhost:8080/index.dart.js:1640:23)
    at invokeClosure_closure.call$0 (http://localhost:8080/index.dart.js:2644:29)
    at _IsolateContext.eval$1 (http://localhost:8080/index.dart.js:1042:23)
    at dart._callInIsolate (http://localhost:8080/index.dart.js:728:26)
    at invokeClosure (http://localhost:8080/index.dart.js:1963:16) 

I'm using the following Dart developer env

Dart Editor version 1.4.0.dev_02_02 (DEV)
Dart SDK version 1.4.0-dev.2.2

I was getting a similar error on the previous version 1.3.

Here is the pubspec.yaml file

name: google_plus_component
description: A pub package
dependencies:
  browser: any
  google_oauth2_client: any

Here's enough of the offending code

import 'package:google_oauth2_client/google_oauth2_browser.dart';

auth() {
  GoogleOAuth2 auth = new GoogleOAuth2(
      "client_id",
      ["https://www.googleapis.com/auth/plus.login"]
  );

  auth.ensureAuthenticated();
}