* Output of `node_modules/.bin/electron --version`: v5.0.0-nightly.20190107
* Operating System (Platform and Version): macOS Mojave 10.14.2 (18C54)
* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): never

**Expected Behavior**
Using navigator.mediaDevices.getDisplayMedia({ video: true }), a native screen picker should appear.

**Actual behavior**
The following error is thrown: NotAllowedError: Permission denied

**Screenshots**
Expected dialog
![image](https://user-images.githubusercontent.com/1120050/51625551-71736500-1f0b-11e9-9a95-1406cad95046.png)
atom/browser/atom_browser_client.cc
AtomBrowserClient::GetSystemSharedURLLoaderFactory() {
  if (!g_browser_process)
    return nullptr;
  return g_browser_process->shared_url_loader_factory();
}
void AtomBrowserClient::OnNetworkServiceCreated(
    network::mojom::NetworkService* network_service) {
  if (!g_browser_process)
    return;
  g_browser_process->system_network_context_manager()->OnNetworkServiceCreated(
      network_service);
}
bool AtomBrowserClient::ShouldBypassCORB(int render_process_id) const {
  
  base::AutoLock auto_lock(process_preferences_lock_);
  auto it = process_preferences_.find(render_process_id);
  return it != process_preferences_.end() && !it->second.web_security;
}
std::string AtomBrowserClient::GetApplicationLocale() {
  if (BrowserThread::CurrentlyOn(BrowserThread::IO))
    return g_io_thread_application_locale.Get();
  return *g_application_locale;
}
bool AtomBrowserClient::ShouldEnableStrictSiteIsolation() {
  
  return true;
}
}