there's code in the component manager guarded by XPCOM_CHECK_PENDING_CIDS which would enable non abused factories not to use their own locking code (abused factories need bug 423633 too). let's just unconditionally enable it. with XPCOM_CHECK_PENDING_CIDS, there is a promise by xpcom that it will not call a factory for a getservice until it finishes the current attempt. and when it succeeds, it would not need to call the factory again.

Comment on attachment 310435 [details] [diff] [review] unconditionally use XPCOM_CHECK_PENDING_CIDS code If we're going to turn this on in production, I'd prefer nsAutoTArray<const nsCID*, 8> so that we don't have to allocate in the common case. And, this will need unit tests.