Issue 3032913: improve AudioTrack recovery time

This issue showed that when an AudioTrack underruns during a too long period
of time and is therefore disabled by audioflinger mixer, it takes an additional
delay of up to 3 seconds to recover.
This fix adds a simple mechanism to recover immediately when the client application
is ready to write data again in the AudioTrack buffer

Also throttle warnings on record overflows

Change-Id: I8b2c71578dd134b9e60a15ee4d91b70f3799cb3d
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index 1510f87..c6990bf 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -42,8 +42,11 @@
 #define CBLK_FORCEREADY_ON      0x0004  // track is considered ready immediately by AudioFlinger
 #define CBLK_FORCEREADY_OFF     0x0000  // track is ready when buffer full
 #define CBLK_INVALID_MSK        0x0008
-#define CBLK_INVALID_ON         0x0008  // track buffer is invalidated by AudioFlinger: must be re-created
-#define CBLK_INVALID_OFF        0x0000
+#define CBLK_INVALID_ON         0x0008  // track buffer is invalidated by AudioFlinger:
+#define CBLK_INVALID_OFF        0x0000  // must be re-created
+#define CBLK_DISABLED_MSK       0x0010
+#define CBLK_DISABLED_ON        0x0010  // track disabled by AudioFlinger due to underrun:
+#define CBLK_DISABLED_OFF       0x0000  // must be re-started
 
 struct audio_track_cblk_t
 {