* Electron version: 1.7.3 - not sure when this was introduced, works fine in latest production build based on 1.4.15
* Operating system: Windows

### Expected behavior

I have three screens connected to my computer. `desktopCapturer.getSources({types: ['screen']})` correctly identifies three sources.

I want to share my first screen and set `chromeMediaSourceId` to the matching id `screen:0:0` in the constraints when requesting the MediaStream using `navigator.mediaDevices.getUserMedia()`. I should get a MediaStream containing a video track with the content of the first screen.

### Actual behavior

The stream returned will show the  content of the second screen. If I ask for the second screen, I get the third screen. If I ask for the third screen, I get a black screen.

### How to reproduce

https://github.com/wireapp/wire-desktop

````
git clone https://github.com/wireapp/wire-desktop.git
npm install
npm run prod
````

* Log in or create a Wire account. Feel free to connect to me (@gregor)
* Start audio or video call
* Click on share your screen
* Select screen to be shared

![electron](https://user-images.githubusercontent.com/10243309/27835989-b897f902-60dd-11e7-8dfc-555b4958fc99.png)
![electron2](https://user-images.githubusercontent.com/10243309/27835988-b8943060-60dd-11e7-881c-f3dfdad6cc65.png)

atom/browser/api/atom_api_desktop_capturer.cc
bool capture_screen,
                                    const gfx::Size& thumbnail_size) {
  webrtc::DesktopCaptureOptions options =
      webrtc::DesktopCaptureOptions::CreateDefault();
#if defined(OS_WIN)
  
  
  
  
  
  
  options.set_disable_effects(false);
#endif
  std::unique_ptr<webrtc::DesktopCapturer> screen_capturer(
      capture_screen ? webrtc::DesktopCapturer::CreateScreenCapturer(options)
                     : nullptr);
  std::unique_ptr<webrtc::DesktopCapturer> window_capturer(
      capture_window ? webrtc::DesktopCapturer::CreateWindowCapturer(options)
                     : nullptr);
  media_list_.reset(new NativeDesktopMediaList(
      std::move(screen_capturer), std::move(window_capturer)));
  media_list_->SetThumbnailSize(thumbnail_size);
  media_list_->StartUpdating(this);
}
void DesktopCapturer::OnSourceAdded(int index) {
}
void DesktopCapturer::OnSourceRemoved(int index) {
}
void DesktopCapturer::OnSourceMoved(int old_index, int new_index) {