Re: simple nsIWebProgressListener question

Dear Christian,

Thanks very much for your help.  I managed to get the final problem
solved regarding the crashed inside nsSampleImplConstructor(). 
Following the sample in nsPrefetchService.cpp.  I realise that
AddProgressListener() should be called inside Observe() function
instead of the nsSampleImpl().  Hence, crashed occurs when
AddProgressListener() is called inside nsSampleImpl().

Once again, thanks a lot.

Regards,
yueweng