1, according to the document at https://crosswalk-project.org/#wiki/Crosswalk-manifest, `local_path` is not for host app, url like `http://xxx` should use other keyword, like `web_url` (maybe not accurate) for chrome's crx manifest. Since there is no such definition in our spec, here you want to support both host and local app with `local_path`.
2. So here the main purpose is to distinguish url from local path, and by default you should take it as local path. here comes my suggestion to use `http://`. `www.google.com` also works as web url, will you handle that? Case is here we are mandatory forcing web developers to write url as `http://www.google.com`.