Create a new browser using the window parameters specified by |windowInfo|. All values will be copied internally and the actual window (if any) will be created on the UI thread. If |request_context| is NULL the global request context will be used. This function can be called on any browser process thread and will not block. The optional |extra_info| parameter provides an opportunity to specify extra information specific to the created browser that will be passed to cef_render_process_handler_t::on_browser_created() in the render process.