Merge "Add null check before invoking onChallengeInterruptFinished"

                    final FaceGenerateChallengeClient previousChallengeOwner =

                            mCurrentChallengeOwner.getInterruptedClient();

                    mCurrentChallengeOwner = null;

                    Slog.d(TAG, "Previous challenge owner: " + previousChallengeOwner);

                    if (previousChallengeOwner != null) {

                        final ClientMonitorCallbackConverter listener =

                                previousChallengeOwner.getListener();

                        if (listener == null) {

                            Slog.w(TAG, "Listener is null");

                        } else {

                            try {

                            previousChallengeOwner.getListener()

                                    .onChallengeInterruptFinished(mSensorId);

                                listener.onChallengeInterruptFinished(mSensorId);

                            } catch (RemoteException e) {

                                Slog.e(TAG, "Unable to notify interrupt finished", e);

                            }

                        }

                    }

                }

            });

        });

    }