BroadcasterHookup(nsIContent* aObservesElement) : mObservesElement(aObservesElement), mResolved(PR_FALSE) {}
BroadcasterHookup(nsXULDocument* aDocument, nsIContent* aObservesElement) : mDocument(aDocument), mObservesElement(aObservesElement), mResolved(PR_FALSE) {}
        BroadcasterHookup(nsIContent* aObservesElement) :            mObservesElement(aObservesElement), mResolved(PR_FALSE) {}