[webcomponents] HTML Imports notes

Hi,

Since last HTML Imports WD is published, I heard some feedback. Most of
them are about the loading order and its sync/async nature. Thanks for
sharing your thought!

At the same time, I found there are some confusion about how it works. As
it's hard for me to capture the underlying thinking in the standard
document, I thought that it might be helpful to informally sketch what's
behind the current design and what we're thinking. So here it is [1]. I
hope this clarifies some of your questions and/or concerns.

If you have any comments, let's talk at coming F2F.

Bests,

[1] https://gist.github.com/omo/9986103

-- 
morrita