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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
web_contents()->SetAudioMuted(muted);
}
bool WebContents::IsAudioMuted() {
  return web_contents()->IsAudioMuted();
}
void WebContents::Print(mate::Arguments* args) {
  PrintSettings settings = { false, false };
  if (args->Length() == 1 && !args->GetNext(&settings)) {
    args->ThrowError();
    return;
  }
  printing::PrintViewManagerBasic::FromWebContents(web_contents())->
      PrintNow(web_contents()->GetMainFrame(),
               settings.silent,
               settings.print_background);
}
void WebContents::PrintToPDF(const base::DictionaryValue& setting,
                             const PrintToPDFCallback& callback) {
  printing::PrintPreviewMessageHandler::FromWebContents(web_contents())->
      PrintToPDF(setting, callback);
}
void WebContents::AddWorkSpace(mate::Arguments* args,
                               const base::FilePath& path) {
  if (path.empty()) {
    args->ThrowError("path cannot be empty");
    return;
  }
  DevToolsAddFileSystem(path);
}
void WebContents::RemoveWorkSpace(mate::Arguments* args,