Ignore events after BluetoothStateManager is destroyed.

Fixes crash.

src/org/thoughtcrime/securesms/webrtc/audio/BluetoothStateManager.java

@@ -19,6 +19,7 @@ import org.thoughtcrime.securesms.logging.Log;
 import org.thoughtcrime.securesms.util.ServiceUtil;
 
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 public class BluetoothStateManager {
 
@@ -37,6 +38,7 @@ public class BluetoothStateManager {
   private       BluetoothScoReceiver        bluetoothScoReceiver;
   private       BluetoothConnectionReceiver bluetoothConnectionReceiver;
   private final BluetoothStateListener      listener;
+  private final AtomicBoolean               destroyed;
 
   private BluetoothHeadset bluetoothHeadset = null;
   private ScoConnection    scoConnection    = ScoConnection.DISCONNECTED;
@@ -48,6 +50,7 @@ public class BluetoothStateManager {
     this.bluetoothScoReceiver        = new BluetoothScoReceiver();
     this.bluetoothConnectionReceiver = new BluetoothConnectionReceiver();
     this.listener                    = listener;
+    this.destroyed                   = new AtomicBoolean(false);
 
     if (this.bluetoothAdapter == null)
       return;
@@ -66,6 +69,8 @@ public class BluetoothStateManager {
   }
 
   public void onDestroy() {
+    destroyed.set(true);
+
     if (bluetoothHeadset != null && bluetoothAdapter != null) {
       this.bluetoothAdapter.closeProfileProxy(BluetoothProfile.HEADSET, bluetoothHeadset);
     }
@@ -137,6 +142,11 @@ public class BluetoothStateManager {
       @RequiresApi(api = Build.VERSION_CODES.HONEYCOMB)
       @Override
       public void onServiceConnected(int profile, BluetoothProfile proxy) {
+        if (destroyed.get()) {
+          Log.w(TAG, "Got bluetooth profile event after the service was destroyed. Ignoring.");
+          return;
+        }
+
         if (profile == BluetoothProfile.HEADSET) {
           synchronized (LOCK) {
             bluetoothHeadset = (BluetoothHeadset) proxy;