Merge "Move sticky cards to the bottom" into rvc-dev

    @VisibleForTesting

    List<ContextualCard> sortCards(List<ContextualCard> cards) {

        // take mContextualCards as the source and do the ranking based on the rule.

        return cards.stream()

        final List<ContextualCard> result = cards.stream()

                .sorted((c1, c2) -> Double.compare(c2.getRankingScore(), c1.getRankingScore()))

                .collect(Collectors.toList());

        final List<ContextualCard> stickyCards = result.stream()

                .filter(c -> c.getCategory() == STICKY_VALUE)

                .collect(Collectors.toList());

        // make sticky cards be at the tail end.

        result.removeAll(stickyCards);

        result.addAll(stickyCards);

        return result;

    }

    @Override