Merge "Fix the reference leak on RemoteCallbackList"

core/java/android/os/RemoteCallbackList.java

@@ -123,6 +123,7 @@ public class RemoteCallbackList<E extends IInterface> {
             IBinder binder = callback.asBinder();
             try {
                 Callback cb = new Callback(callback, cookie);
+                unregister(callback);
                 binder.linkToDeath(cb, 0);
                 mCallbacks.put(binder, cb);
                 return true;