[webkit-dev] Blob changes to SecurityOrigin.cpp

[Adam Barth]

I was looking at SecurityOrigin.cpp today and I saw a bunch of code
relating to Blob URLs.  I don't really understand why this code is
correct.  Would someone be willing to explain it to me?

Some specific questions:

1) Why do blob URLs get exception from the unique origin check?  How
does that interact with the HTML5 sandboxing model?
2) Why does SecurityOrigin::canLoad take a document as an argument?
What are the semantics of this parameter?  In particular, why does a
SecurityOrigin::canLoad ignore |this| when called with a document
argument on a blob URL?  That seems like a very bad idea.

In general, I'd prefer if folks checked with Sam or me before adding
loopholes in SecurityOrigin.  Although the class might appear simple,
it's quite subtle.

Adam