AudioTrack: Use original flags during track recreation

Also the OFFLOAD and DIRECT flags aren't denied by server.

authored-by: Pavan Chikkala<pavanc@codeaurora.org>
Bug: 27554925
Change-Id: I6fd6b129928af4513bb0cba271019288605310f8
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index e0fb603..69dc062 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -949,9 +949,11 @@
 
     uint32_t                mUnderrunCountOffset;   // updated when restoring tracks
 
-    audio_output_flags_t    mFlags;
-        // const after set(), except for bits AUDIO_OUTPUT_FLAG_FAST and AUDIO_OUTPUT_FLAG_OFFLOAD.
-        // mLock must be held to read or write those bits reliably.
+    audio_output_flags_t    mFlags;                 // same as mOrigFlags, except for bits that may
+                                                    // be denied by client or server, such as
+                                                    // AUDIO_OUTPUT_FLAG_FAST.  mLock must be
+                                                    // held to read or write those bits reliably.
+    audio_output_flags_t    mOrigFlags;             // as specified in constructor or set(), const
 
     bool                    mDoNotReconnect;