Css sourcemaps are not loaded / displayed when using styleUrls: [...] #9664

I'm submitting a ... (check one with "x")

[X] bug report
[ ] feature request
[ ] support request

Current behavior
When using the styleUrls to load a stylesheet with ecapsulation: ViewEncapsulation.None it does not properly load the sourcemap that is associated with it. Nor does it work when using inline css sourcemaps.

Expected/desired behavior
It should within the browser show the sourcemap of the css when opening the development tools. Just like it does when you use sourcemaps normally within inline <style> tags.

Reproduction of the problem
Within the plunker example below you can see that the native implementation works yet when the style is specified using:

@Component({
  selector: 'my-app',
  moduleId: __moduleName,
  styleUrls: ['style.css'],
  encapsulation: ViewEncapsulation.None,
  providers: [],
  template: `<div class="test"> I should be blue </div>`
})
export class App {

It no longer works and the source map is not linked to the css that is inlined.

Plnkr link
https://plnkr.co/edit/skKLA7oxnVTSmIkI2ipw?p=preview

What is the motivation / use case for changing the behavior?

This would make it possible to more easily include style sheets for specific routes while making sure a Frontend designer can alter the sass without requiring him/her to constantly search for the sass that is associated with the inline css.

Please tell us about your environment:

Windows 10 Version 1511

• Angular version: 2.0.0-rc.3
• Browser: [all]
• Language: [all]