- add a new nsIWebProgressListener2 interface, inheriting from
nsIWebProgressListener, providing a 64-bit onProgressChange method
- make nsITransfer inherit from that interface, and remove an unused
progressListener attribute
- make webbrowserpersist support listeners that implement
nsIWebProgressListener2, and give them 64-bit progress values
- make nsIHelperAppLauncher's listener setWebProgressListener function take an
nsIWebProgressListener2 interface
And fix up all implementations according to that.