Camera2/3: Avoid shutdown race in callback processor.

It's possible, during shutdown, for callback processor's heap to be
destroyed when it's about to send the callback back to the user.
Properly copy the heap reference to a local variable before unlocking
the mutex.

Bug: 9485959
Change-Id: I301347b77145f19c7ac721b9127dc74f122acce2
1 file changed