I just wanted to let people know that there was a recent insiduous
little change to imgILoader. libpr0n will no longer hold a strong ref
to the imgIDecoderObserver you pass in. The goal is to eliminate the
reference cycles you used to get with caller holding the imgIRequest and
the request holding the caller (QIed to imgIDecoderObserver).
But the point is, if you were depending on libpr0n to keep the
imgIDecoderObserver alive, you can't depend on that anymore.
