Tracks: log internalTrackId in metrics

This makes associating tracks in the audioflinger dumpsys
with metrics logging easier.

Test: adb shell dumpsys media.metrics
Bug: 181242710
Change-Id: Ic7e3c35765bad786f5a97c06152da786b78c8aa8
diff --git a/media/libmediametrics/include/MediaMetricsConstants.h b/media/libmediametrics/include/MediaMetricsConstants.h
index a181b06..0f80d35 100644
--- a/media/libmediametrics/include/MediaMetricsConstants.h
+++ b/media/libmediametrics/include/MediaMetricsConstants.h
@@ -123,6 +123,7 @@
 
 #define AMEDIAMETRICS_PROP_FRAMECOUNT     "frameCount"     // int32
 #define AMEDIAMETRICS_PROP_INPUTDEVICES   "inputDevices"   // string value
+#define AMEDIAMETRICS_PROP_INTERNALTRACKID "internalTrackId" // int32
 #define AMEDIAMETRICS_PROP_INTERVALCOUNT  "intervalCount"  // int32
 #define AMEDIAMETRICS_PROP_LATENCYMS      "latencyMs"      // double value
 #define AMEDIAMETRICS_PROP_LOGSESSIONID   "logSessionId"   // hex string, "" none