Avoid overhead of redundant task manipulation when it gains focus

        // Shift all activities with this task up to the top

        // of the stack, keeping them in the same internal order.

        boolean first = true;

        while (pos >= 0) {

            ActivityRecord r = (ActivityRecord)mHistory.get(pos);

            if (localLOGV) Slog.v(

                TAG, "At " + pos + " ckp " + r.task + ": " + r);

            boolean first = true;

            if (r.task.taskId == task) {

                if (localLOGV) Slog.v(TAG, "Removing and adding at " + top);

                mHistory.remove(pos);