<!--
Thanks for opening an issue! A few things to keep in mind:

- The issue tracker is only for bugs and feature requests.
- Before reporting a bug, please try reproducing your issue against
  the latest version of Electron.
- If you need general advice, join our Slack: http://atom-slack.herokuapp.com
-->

* Electron version: 1.6.1
* Operating system: macOS

### Expected behavior

navigator.geolocation.getCurrentPosition runs in background

### Actual behavior

the entire UI is frozen

### How to reproduce

```js
    navigator.geolocation.getCurrentPosition((pos) => {
      console.log('POS: ' + pos);
    }, (err) => {
      console.log('Geolocation error: ', err);
    }, {enableHighAccuracy: false});
```
atom/browser/common_web_contents_delegate.cc
}
void CommonWebContentsDelegate::InitWithWebContents(
    content::WebContents* web_contents,
    AtomBrowserContext* browser_context) {
  browser_context_ = browser_context;
  web_contents->SetDelegate(this);
  printing::PrintViewManagerBasic::CreateForWebContents(web_contents);
  printing::PrintPreviewMessageHandler::CreateForWebContents(web_contents);
  
  web_contents_.reset(brightray::InspectableWebContents::Create(web_contents));
  web_contents_->SetDelegate(this);
}
void CommonWebContentsDelegate::SetOwnerWindow(NativeWindow* owner_window) {
  SetOwnerWindow(GetWebContents(), owner_window);
}
void CommonWebContentsDelegate::SetOwnerWindow(
    content::WebContents* web_contents, NativeWindow* owner_window) {
  owner_window_ = owner_window->GetWeakPtr();
  NativeWindowRelay* relay = new NativeWindowRelay(owner_window_);
  web_contents->SetUserData(relay->key, relay);
}
void CommonWebContentsDelegate::DestroyWebContents() {
  web_contents_.reset();
}
content::WebContents* CommonWebContentsDelegate::GetWebContents() const {
  if (!web_contents_)
    return nullptr;
  return web_contents_->GetWebContents();
}
content::WebContents*