Refactor code related to I/O handles to reduce chance for leaks

The AudioRecord input handle code was refactored earlier
to fix a potential handle leak, and to simplify the code:
    > Change-Id: I124dce344b1d11c2dd66ca5e2c9aec0c52c230e2

This changelist refactors AudioTrack similarly,
and adds further cleanup of both AudioTrack and AudioRecord.

We attempt to implement the rules for referencing counting I/O handles,
but there is still the possibility of a handle leak if the client process
dies after allocating the handle reference but before releasing it.
That issue is being tracked separately.

Details:
 - AudioSystem::getOutput() is now called within createTrack_l
 - restoreTrack_l was missing offload info
   now it has the info available,
   but is not yet being called for offloaded tracks
 - AudioTrack::getOutput() is now const
 - Remove getOutput_l()

Change-Id: I44a0a623d24fc5847bcac0939c276400568adbca

1 files changed, 2 insertions, 3 deletions

diff --git a/include/media/AudioRecord.h b/include/media/AudioRecord.h
index 45134c4..3d839fc 100644
--- a/include/media/AudioRecord.h
+++ b/include/media/AudioRecord.h
@@ -486,12 +486,11 @@ private:
     int                     mSessionId;
     transfer_type           mTransfer;
 
-    audio_io_handle_t       mInput;             // returned by AudioSystem::getInput()
-
-    // Next 3 fields may be changed if IAudioRecord is re-created, but always != 0
+    // Next 4 fields may be changed if IAudioRecord is re-created, but always != 0
     sp<IAudioRecord>        mAudioRecord;
     sp<IMemory>             mCblkMemory;
     audio_track_cblk_t*     mCblk;              // re-load after mLock.unlock()
+    audio_io_handle_t       mInput;             // returned by AudioSystem::getInput()
 
     int                     mPreviousPriority;  // before start()
     SchedPolicy             mPreviousSchedulingGroup;