Resolves crash in AudioTrack.flush() on Android

webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java

Index: webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java
diff --git a/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java b/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java
index 6800a7c0232719c7d63b5fda817f7538b7797d7c..ab55567b3caa10dcda14a477ec4c6728a68cf458 100644
--- a/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java
+++ b/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioTrack.java
@@ -173,12 +173,14 @@ public class WebRtcAudioTrack {
       // Stops playing the audio data. Since the instance was created in
       // MODE_STREAM mode, audio will stop playing after the last buffer that
       // was written has been played.
-      final AudioTrack at = audioTrack;
-      if (at != null) {
+      if (audioTrack != null) {
         Logging.d(TAG, "Stopping the audio track...");
-        at.stop();
-        Logging.d(TAG, "The audio track has now been stopped.");
-        at.flush();
+        try {
+          audioTrack.stop();
+          Logging.d(TAG, "The audio track has now been stopped.");
+        } catch (IllegalStateException e) {
+          Logging.e(TAG, "AudioTrack.stop failed: " + e.getMessage());
+        }
       }
     }