AudioTrack: error reporting for getTimestamp()

Add a new getTimestamp() method that returns an error code.

Bug: 21886109.
Bug: 22202349.
Bug: 17548098.

Change-Id: Ib072dd3442de79bab9aca77c3c33b0790b492154
(cherry picked from commit 4e1ccd370fc268f3207c5baee08ac8c943c3fdf9)
3 files changed