Revamp the uri loader to excusively use AsyncRead instead of AsyncOpen and AsyncRead. With these changes,
we now only need to add the ability to retarget to our protocol channels instead of requiring both
retargeting and AsyncOpen support.
In order to do this, the DocumentOpenInfo object needed to become a nsIStreamListener instead of just
a stream observer.
git-svn-id: svn://10.0.0.236/trunk@53544 18797224-902f-48f8-a5cc-f745e15eee43
87ce7ec67c