Fix ConcurrentModificationException in MultiConnectionKeeper (#3553)

Co-authored-by: Marvin W <git@larma.de>

Author: DaVinci9196

play-services-base/src/main/java/org/microg/gms/common/MultiConnectionKeeper.java

@@ -33,13 +33,14 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import static android.os.Build.VERSION.SDK_INT;
 import static org.microg.gms.common.Constants.GMS_PACKAGE_NAME;
@@ -201,11 +202,11 @@ public synchronized void unbind(String action, ServiceConnection connection) {
     public class Connection {
         private final String actionString;
         private final boolean requireMicrog;
-        private final Set<ServiceConnection> connectionForwards = new HashSet<ServiceConnection>();
-        private boolean bound = false;
-        private boolean connected = false;
-        private IBinder binder;
-        private ComponentName component;
+        private final Set<ServiceConnection> connectionForwards = Collections.newSetFromMap(new ConcurrentHashMap<>());
+        private volatile boolean bound = false;
+        private volatile boolean connected = false;
+        private volatile IBinder binder;
+        private volatile ComponentName component;
         private ServiceConnection serviceConnection = new ServiceConnection() {
             @Override
             public void onServiceConnected(ComponentName componentName, IBinder iBinder) {