Function browser_host_create_browser_sync 

pub fn browser_host_create_browser_sync(
    window_info: Option<&WindowInfo>,
    client: Option<&mut Client>,
    url: Option<&CefString>,
    settings: Option<&BrowserSettings>,
    extra_info: Option<&mut DictionaryValue>,
    request_context: Option<&mut RequestContext>,
) -> Option<Browser>

See cef_browser_host_create_browser_sync for more documentation.