* 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 true;
    }
  }
  
  auto src_url = current_instance->GetSiteURL();
  return !IsSameWebSite(browser_context, src_url, url);
}
bool AtomBrowserClient::NavigationWasRedirectedCrossSite(
    content::BrowserContext* browser_context,
    content::SiteInstance* current_instance,
    content::SiteInstance* speculative_instance,
    const GURL& dest_url,
    bool has_response_started) const {
  bool navigation_was_redirected = false;
  if (has_response_started) {
    navigation_was_redirected = !IsSameWebSite(
        browser_context, current_instance->GetSiteURL(), dest_url);
  } else {
    navigation_was_redirected =
        speculative_instance &&
        !IsSameWebSite(browser_context, speculative_instance->GetSiteURL(),
                       dest_url);
  }
  return navigation_was_redirected;
}
void AtomBrowserClient::AddProcessPreferences(