Reporting audio device underrun counter

Bug: webrtc:10884
Change-Id: I35636fcbc1e2a19a89242379cdff6ec5c12fd21a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/149200
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Alex Narest <alexnarest@google.com>
Cr-Commit-Position: refs/heads/master@{#28874}

sdk/android/src/java/org/webrtc/audio/WebRtcAudioTrack.java

@@ -342,6 +342,19 @@ class WebRtcAudioTrack {
     return audioManager.getStreamVolume(AudioManager.STREAM_VOICE_CALL);
   }
 
+  @CalledByNative
+  private int GetPlayoutUnderrunCount() {
+    if (Build.VERSION.SDK_INT >= 24) {
+      if (audioTrack != null) {
+        return audioTrack.getUnderrunCount();
+      } else {
+        return -1;
+      }
+    } else {
+      return -2;
+    }
+  }
+
   private void logMainParameters() {
     Logging.d(TAG,
         "AudioTrack: "