mshtml: Removed return to ensure AddRef is called on an internal interface

[Jacek Caban]

On 02/04/15 11:26, Nikolay Sivov wrote:
> On 02.04.2015 12:23, Piotr Caban wrote:
>> On 04/02/15 11:16, Alistair Leslie-Hughes wrote:
>>> But "*ppv·=·&This->IHTMLDOMNode_iface" does. Without an AddRef it 
>>> causes
>>> an imbalance of AddRef/Release.
>>>
>>> So, should it be returning IHTMLDOMNode_iface then?
>> I'm not sure if I understand this code correctly but I think that
>> nsCycleCollectionISupports is an empty class that only needs a pointer.
>> There's no imbalance of AddRef/Release because Release will be never
>> called in this case.
>>
>
> I think it's just a marker, so gecko knows that this node is included 
> in collection business.

Yes, it is a special case, see [1]. It's used to cannonicalize interface 
pointer so that it may be used as an identifier in cycle collector 
graph. It's not a real interface and it should not cause reference change.

Alistair, your bug is probably somewhere else. If your patch "fixed" it, 
it indeed suggests a refcount-related problem somewhere else.

Cheers,
Jacek

[1] 
http://hg.mozilla.org/mozilla-central/file/944fb6e682b8/xpcom/glue/nsCycleCollectionParticipant.h#l23