Merge "Don't play transitions if keyguard didn't register" into udc-qpr-dev

            @NonNull SurfaceControl.Transaction startTransaction,

            @NonNull SurfaceControl.Transaction finishTransaction,

            @NonNull TransitionFinishCallback finishCallback) {

        if (remoteHandler == null) {

            ProtoLog.e(ShellProtoLogGroup.WM_SHELL_TRANSITIONS,

                    "missing handler for keyguard %s transition", description);

            return false;

        }

        ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TRANSITIONS,

                "start keyguard %s transition, info = %s", description, info);

        try {

            mStartedTransitions.put(transition,

                    new StartedTransition(info, finishTransaction, remoteHandler));