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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
if (embedder) {
    NativeWindow* owner_window = nullptr;
    auto relay = NativeWindowRelay::FromWebContents(embedder->web_contents());
    if (relay) {
      owner_window = relay->window.get();
    }
    if (owner_window)
      SetOwnerWindow(owner_window);
    content::RenderWidgetHostView* rwhv =
        web_contents()->GetRenderWidgetHostView();
    if (rwhv) {
      rwhv->Hide();
      rwhv->Show();
    }
  }
}
v8::Local<v8::Value> WebContents::DevToolsWebContents(v8::Isolate* isolate) {
  if (devtools_web_contents_.IsEmpty())
    return v8::Null(isolate);
  else
    return v8::Local<v8::Value>::New(isolate, devtools_web_contents_);
}
v8::Local<v8::Value> WebContents::Debugger(v8::Isolate* isolate) {
  if (debugger_.IsEmpty()) {
    auto handle = atom::api::Debugger::Create(isolate, web_contents());
    debugger_.Reset(isolate, handle.ToV8());
  }
  return v8::Local<v8::Value>::New(isolate, debugger_);
}
void WebContents::BuildPrototype(v8::Isolate* isolate,