* Output of `node_modules/.bin/electron --version`: 4.0.0-beta.7
* Operating System (Platform and Version): OS X Mojave 10.14.1
* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): Never seen it work in any version available

**Expected Behavior**

webContents select-bluetooth-device should allow to select a device from the list and pair it.

**Actual behavior**

- When you try to pair a device in a webview, electron throws an error and force exit.
- The deviceList only contains/shows 1 device, even when there's multiple BLE devices (Chrome shows all of them).

**To Reproduce**
https://gist.github.com/4eveRS/9ade679271cc536da97b692492e048af

**Additional Information**
If there's no easy fix for this issue, is it possible to disable bluetooth support at all ?
Tried with 

```
app.commandLine.appendSwitch('enable-web-bluetooth', false);
app.commandLine.appendSwitch("enable-experimental-web-platform-features", false);
```

and it didn't work.
atom/browser/lib/bluetooth_chooser.cc
const std::string& device_id) {
  if (device_id.empty()) {
    handler.Run(content::BluetoothChooser::Event::CANCELLED, device_id);
  } else {
    handler.Run(content::BluetoothChooser::Event::SELECTED, device_id);
  }
}
}  
BluetoothChooser::BluetoothChooser(api::WebContents* contents,
                                   const EventHandler& event_handler)
    : api_web_contents_(contents), event_handler_(event_handler) {}
BluetoothChooser::~BluetoothChooser() {}
void BluetoothChooser::SetAdapterPresence(AdapterPresence presence) {
  switch (presence) {
    case AdapterPresence::ABSENT:
    case AdapterPresence::POWERED_OFF:
      event_handler_.Run(Event::CANCELLED, "");
      break;
    case AdapterPresence::POWERED_ON:
      break;
  }
}
void BluetoothChooser::ShowDiscoveryState(DiscoveryState state) {