Called prior to calling Cef.Shutdown, this disposes of any remaining
ChromiumWebBrowser instances. In WPF this is used from Dispatcher.ShutdownStarted
to release the unmanaged resources held by the ChromiumWebBrowser instances.
Generally speaking you don't need to call this yourself.
CefSharp.Core (in CefSharp.Core.dll) Version: 188.8.131.52
public static void PreShutdown()