Since fb_post and dequeueBuffer may be called
from different threads, it might happen
that both wait for available buffer causig
both threads to go in sleep. To solve this
problem we add lockBuffer implementation
and remove waits from fb_post and dequeueBuffer.
This will also be consistent with native window
implementation.
Change-Id: Id5e6e2feac5153156fabd9266b0c1cd5a5681514
49008be4a3