Remote audio submix: blocking writes and sleeping reads.

Change how the remote audio submix is handling piping audio
 through the pipe:
 - use a MonoPipe as audio sink for blocking writes,
 - use a MonoPipeReader as audio source for non blocking reads,
  and keep track of when recording started to align the
  time at which the in_read() call should return with the
  projected time of the recording duration.

Change-Id: I8b0f8c56a0486806101e272dfbf9c6d2d1c11112
1 file changed