Register a custom scheme. This function should not be called for the built-in HTTP, HTTPS, FILE, FTP, ABOUT and DATA schemes.

See cef_scheme_options_t for possible values for |options|.

This function may be called on any thread. It should only be called once per unique |scheme_name| value. If |scheme_name| is already registered or if an error occurs this function will return false (0).

Structure that creates cef_resource_handler_t instances for handling scheme requests. The functions of this structure will always be called on the IO