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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
atom::AtomBrowserClient::SuppressRendererProcessRestartForOnce();
  web_contents()->GetController().GoToOffset(offset);
}
const std::string WebContents::GetWebRTCIPHandlingPolicy() const {
  return web_contents()->
    GetMutableRendererPrefs()->webrtc_ip_handling_policy;
}
void WebContents::SetWebRTCIPHandlingPolicy(
    const std::string& webrtc_ip_handling_policy) {
  if (GetWebRTCIPHandlingPolicy() == webrtc_ip_handling_policy)
    return;
  web_contents()->GetMutableRendererPrefs()->webrtc_ip_handling_policy =
    webrtc_ip_handling_policy;
  content::RenderViewHost* host = web_contents()->GetRenderViewHost();
  if (host)
    host->SyncRendererPrefs();
}
bool WebContents::IsCrashed() const {
  return web_contents()->IsCrashed();
}
void WebContents::SetUserAgent(const std::string& user_agent,
                               mate::Arguments* args) {
  web_contents()->SetUserAgentOverride(user_agent);
}
std::string WebContents::GetUserAgent() {
  return web_contents()->GetUserAgentOverride();
}
bool WebContents::SavePage(const base::FilePath& full_file_path,