HttpRequest.open is throwing a _uri error about strings?

Question

I end up with a function which was working until recently it seems. I have the following code:

String url = "https://this.is.a.test.com/hello?varA=false";
var request = new HttpRequest();
request.open("GET", url);
...

The following error throws when attempting to call open, so i ensured that the URL Link is correct, but referencing it through a browser. It also works.

type '_Uri' is not a subtype of type 'String' of 'url' where

_Uri is from dart:core

String is from dart:core

At first, I thought the link was wrong until I had tested it. When i looked at what open did it referenced: html_dartium.dart and i noticed the following definition, which is what my intellisense allowed me to jump to:

@DomName('XMLHttpRequest.open')
@DocsEditable()
void open(String method, String url, {bool async, String user, String password}) {
  if (async == null && user == null && password == null) {
    _blink.BlinkXMLHttpRequest.instance.open_Callback_2_(this, method, url);
  } else {
    _blink.BlinkXMLHttpRequest.instance.open_Callback_5_(this, method, url, async, user, password);
  }
}

I am not sure what is going on here with this package. I am also unsure where this was pulled from, as i am thinking something may have been broke,through another source. Right now I am using:

browser: ^0.10.0
polymer: ^1.0.0-rc.16
web_components: ^0.12.0
polymer_elements: ^1.0.0-rc.8
uuid: ^0.5.1
http: 0.11.3+7

any nothing is quite jumping out at me.

As of right now, this is an error in Dartium only, so I am guessing it is just an issue with Checked mode being permanently on. I tried the same in Chrome and it referenced and downloaded the file just fine.

Has anyone else encountered this, and have a fix so that it will continue?