From:  Mark Hammond <>
Date:  20 Aug 2013 14:26:08 Hong Kong Time

Re: Forcing every request from a docShell to use LOAD_ANONYMOUS


On 19/08/2013 11:37 PM, Boris Zbarsky wrote:
> On 8/19/13 4:45 AM, Mark Hammond wrote:
>> nsLoadGroup::MergeLoadFlags() isn't actually called here
> Hmm.  This is only called for sub-requests.  Worse yet, the default load
> request will clobber the loadgroup flags.  See
> nsLoadGroup::SetDefaultLoadRequest.

I experimented a little with this, and it (almost) works.  I initially did:

   docShell.loadGroup.defaultLoadRequest.loadFlags |= 

before making the loadURI call - but this didn't work as the ::Stop() 
call made by loadURI (we pass the LOAD_FLAGS_STOP_CONTENT flag) causes 
the defaultRequest to be set to null - so the flag is lost.

I then changed it so that call was made *after* loadURI, which worked 
fine in a local  element, but failed to work in a .  Very quick debugging implies that this might be due to 
the fact the request has progressed before that flag gets set on the 
channel in the parent process.

So tl;dr - it seems very difficult to set this flag on the 

I have verified that using an nsIWebProgress listener does seem to work 
though - I just look for all notifications with STATE_START | 
STATE_IS_REQUEST and set the flag at that time - and this also doesn't 
need the tweak to MergeLoadFlags.  Seeing as we already need a progress 
listener for a different bug, this seems the most pragmatic way forward.

Thanks for everyone's help.


> So you need to set the flag explicitly on the document load in docshell
> _and_ propagate it in MergeLoadFlags.  On the other hand, you don't need
> to manually twiddle the flags on the loadgroup: setting them on the
> document load request will handle it for the subresources.
> -Boris