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* 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/api/atom_api_web_contents.cc
auto relay =
          NativeWindowRelay::FromWebContents(embedder_->web_contents());
      if (relay)
        owner_window = relay->window.get();
    }
    if (owner_window)
      SetOwnerWindow(owner_window);
  }
  const content::NavigationController* controller =
      &web_contents->GetController();
  registrar_.Add(this, content::NOTIFICATION_NAV_ENTRY_PENDING,
                 content::Source<content::NavigationController>(controller));
  Init(isolate);
  AttachAsUserData(web_contents);
}
WebContents::~WebContents() {
  
  if (managed_web_contents()) {
    
    
    if (type_ == WEB_VIEW)
      guest_delegate_->Destroy();
    
    
    
    RenderViewDeleted(web_contents()->GetRenderViewHost());
    WebContentsDestroyed();
  }
}
bool WebContents::DidAddMessageToConsole(content::WebContents* source,