SurfaceComposerClient now only exist on the WindowManager side,
the client side uses the new SurfaceClient class, which only
exposes what a client needs.
also instead of keeping mappings from IBinder to SurfaceComposerClients
we have a SurfaceClient per Surface (referring to the same IBinder), this
is made possible by the fact that SurfaceClient is very light.
Change-Id: I6a1f7015424f07871632a25ed6a502c55abfcfa6
this change introduces R/W locks in the right places.
on the server-side, it guarantees that setBufferCount()
is synchronized with "retire" and "resize".
on the client-side, it guarantees that setBufferCount()
is synchronized with "dequeue", "lockbuffer" and "queue"
