aaudio: lock transport methods
The start/pause/stop/flush/close and other binder methods
need to be thread safe. They do not need to run
in parallel. So a lock was added for each.
Where virtual methods are needed, the locked method calls
a corresponding _l submethod, eg. stop() calls stop_l().
The close logic was also simplified because the "pending"
technique is not needed now that we have the locks.
It was only needed because a close could have occured
while in the middle of another method.
Bug: 153358911
Test: adb logcat *:F
Test: in another window: test_binder_start_storm
Test: There should be no fatal error in the logcat.
Test: atest CtsNativeMediaAAudioTestCases
Change-Id: I5920cf78af4501856756c5c2fc8e77758232508a
Merged-In: I5920cf78af4501856756c5c2fc8e77758232508a
12 files changed
