<!--
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.h
void DevToolsSearchInPath(int request_id,
                            const std::string& file_system_path,
                            const std::string& query) override;
  
#if defined(TOOLKIT_VIEWS)
  gfx::ImageSkia GetDevToolsWindowIcon() override;
#endif
#if defined(USE_X11)
  void GetDevToolsWindowWMClass(
      std::string* name, std::string* class_name) override;
#endif
 private:
  
  void OnDevToolsSaveToFile(const std::string& url);
  
  void OnDevToolsAppendToFile(const std::string& url);
  
  void OnDevToolsIndexingWorkCalculated(int request_id,
                                        const std::string& file_system_path,
                                        int total_work);
  void OnDevToolsIndexingWorked(int request_id,
                                const std::string& file_system_path,
                                int worked);
  void OnDevToolsIndexingDone(int request_id,
                              const std::string& file_system_path);
  void OnDevToolsSearchCompleted(int request_id,
                                 const std::string& file_system_path,
                                 const std::vector<std::string>& file_paths);
  
  void SetHtmlApiFullscreen(bool enter_fullscreen);