Impl dynamic page loading about ioweb2015 HOT 2 CLOSED

I agree with the appropriate. 2 is the big one that simplifies things quit a bit. It means we dont need special logic at page load time to reconstruct the deep link.

It replicates what polymer-project.org does: https://github.com/Polymer/docs/blob/master/js/app.js#L79

There are two gotchas we ned to watch out for:

1. Vulcanizing polymer elements. If we have separate vulcanized bundles for each page (we should for perf), any shared components used on multiple pages need to be moved to the main page's bundle and excluded from the subpage's vulcanized bundle. Otherwise, when you navigate back to a page, there will be a "x element has already been registered" error.

   We'd rely on the URL deduping of imports. For example, it's ok if the main page /app/elements/elements.vulcanized.html gets re-requested on page navigation. It'll be de-duped.

   This might be an interesting case for SW modifying responses.

2. IIRC, custom elements in the xhr'd document are not upgraded. This means they won't have their correct prototype yet (e.g. can't access properties/methods). Example: https://github.com/Polymer/docs/blob/master/js/app.js#L137

from ioweb2015.

Fixed by implementing app/scripts/router.js

from ioweb2015.