This adds a new flag, URI_IS_LOCAL_RESOURCE, to nsIProtocolHandler that allows
something of this protocol to be registered in chrome.
This changeset removes a runtime check every time we open a chrome channel to
see if it is remote to a registration time check that checks flags. The old
code could be easily worked around, and allowed for remote resources to be used.
r=bsmedberg
r=bz
sr=bz
