libaaudio: add callback API

Bug: 36489240
Test: write_sine_callback, input_monitor_callback
Change-Id: I27d79954f7f9de60eb779b47923de87572dc017e
Signed-off-by: Phil Burk <philburk@google.com>
(cherry picked from commit 2ba6e66e16c859cfdbd49c44be4af2a382ca0f49)
1 file changed