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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.h
const base::string16& channel,
                      const base::ListValue& args);
  
  void SendInputEvent(v8::Isolate* isolate, v8::Local<v8::Value> input_event);
  
  void BeginFrameSubscription(mate::Arguments* args);
  void EndFrameSubscription();
  
  void StartDrag(const mate::Dictionary& item, mate::Arguments* args);
  
  
  void CapturePage(mate::Arguments* args);
  
  void SetSize(const SetSizeParams& params);
  bool IsGuest() const;
  
  bool IsOffScreen() const;
  void OnPaint(const gfx::Rect& dirty_rect, const SkBitmap& bitmap);
  void StartPainting();
  void StopPainting();
  bool IsPainting() const;
  void SetFrameRate(int frame_rate);
  int GetFrameRate() const;
  void Invalidate();
  
  void SetZoomLevel(double level);
  double GetZoomLevel();
  void SetZoomFactor(double factor);
  double GetZoomFactor();