The motivation is to make fileembed play
nicely with http.FileServer, particularly
when index.html is involved.
Why add Listable to Files?
* Don't change behavior for existing integrations
* Don't make it too easy for developers to
accidentally leak potentially private
information
Change-Id: I3f4fd3457b606ee98e5f4b117ff9b87e1230c589
large .js files).
We will need this when we start getting large js
files generated when using the closure library.
Change-Id: Iaecacd54c3d08637918b1afd420fb90f1a84aabb