nvda

637e31f8 - Use PostMessage and an event instead of SendMessage to initialise virtual buffer backend render threads.

Use PostMessage and an event instead of SendMessage to initialise virtual buffer backend render threads. This is necessary for Firefox multi-process. When we use SendMessage to do this, outgoing cross-process COM calls fail with RPC_E_CANTCALLOUT_ININPUTSYNCCALL; see Mozilla bug 1297549 comment 14. We avoid this by instead using PostMessage and waiting on an event.