* 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
return g_browser_client;
}
void AtomBrowserClient::SetApplicationLocale(const std::string& locale) {
  if (!BrowserThread::IsThreadInitialized(BrowserThread::IO) ||
      !base::PostTaskWithTraits(
          FROM_HERE, {BrowserThread::IO},
          base::BindOnce(&SetApplicationLocaleOnIOThread, locale))) {
    g_io_thread_application_locale.Get() = locale;
  }
  *g_application_locale = locale;
}
AtomBrowserClient::AtomBrowserClient() {
  DCHECK(!g_browser_client);
  g_browser_client = this;
}
AtomBrowserClient::~AtomBrowserClient() {
  DCHECK(g_browser_client);
  g_browser_client = nullptr;
}
content::WebContents* AtomBrowserClient::GetWebContentsFromProcessID(
    int process_id) {
  
  
  if (base::ContainsKey(pending_processes_, process_id))
    return pending_processes_[process_id];
  
  
  return WebContentsPreferences::GetWebContentsFromProcessID(process_id);
}
bool AtomBrowserClient::ShouldForceNewSiteInstance(