https://travis-ci.org/github/bitcoin/bitcoin/jobs/679885530#L8791
if (result.status == ScanResult::FAILURE) {
            int64_t time_max;
            CHECK_NONFATAL(chain().findBlock(result.last_failed_block, FoundBlock().maxTime(time_max)));
            return time_max + TIMESTAMP_WINDOW + 1;
        }
    }
    return startTime;
}
/**
 * Scan the block chain (starting in start_block) for transactions
 * from or to us. If fUpdate is true, found transactions that already
 * exist in the wallet will be updated.
 *
 * @param[in] start_block Scan starting block. If block is not on the active
 *                        chain, the scan will return SUCCESS immediately.
 * @param[in] start_height Height of start_block
 * @param[in] max_height  Optional max scanning height. If unset there is
 *                        no maximum and scanning can continue to the tip
 *
 * @return ScanResult returning scan information and indicating success or
 *         failure. Return status will be set to SUCCESS if scan was
 *         successful. FAILURE if a complete rescan was not possible (due to
 *         pruning or corruption). USER_ABORT if the rescan was aborted before
 *         it could complete.
 *
 * @pre Caller needs to make sure start_block (and the optional stop_block) are on
 * the main chain after to the addition of any new keys you want to detect
 * transactions for.
 */
CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_block, int start_height, Optional<int> max_height, const WalletRescanReserver& reserver, bool fUpdate)