* 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
switch (state) {
    case DiscoveryState::FAILED_TO_START:
      event_handler_.Run(Event::CANCELLED, "");
      break;
    case DiscoveryState::IDLE:
      if (device_list_.empty()) {
        auto event =
            ++num_retries_ > kMaxScanRetries ? Event::CANCELLED : Event::RESCAN;
        event_handler_.Run(event, "");
      } else {
        bool prevent_default = api_web_contents_->Emit(
            "select-bluetooth-device", device_list_,
            base::Bind(&OnDeviceChosen, event_handler_));
        if (!prevent_default) {
          auto device_id = device_list_[0].device_id;
          event_handler_.Run(Event::SELECTED, device_id);
        }
      }
      break;
    case DiscoveryState::DISCOVERING:
      break;
  }
}
void BluetoothChooser::AddOrUpdateDevice(const std::string& device_id,