Simplify similar strings by extracting the same prefix.

constexpr char kDohPortString[] = "443";

constexpr char kDotPortString[] = "853";

const std::string kDohFlag("persist.device_config.netd_native.doh");

const std::string kDohQueryTimeoutFlag("persist.device_config.netd_native.doh_query_timeout_ms");

const std::string kDohProbeTimeoutFlag("persist.device_config.netd_native.doh_probe_timeout_ms");

const std::string kDohIdleTimeoutFlag("persist.device_config.netd_native.doh_idle_timeout_ms");

const std::string kDohSessionResumptionFlag(

        "persist.device_config.netd_native.doh_session_resumption");

const std::string kDohEarlyDataFlag("persist.device_config.netd_native.doh_early_data");

const std::string kDotAsyncHandshakeFlag("persist.device_config.netd_native.dot_async_handshake");

const std::string kDotMaxretriesFlag("persist.device_config.netd_native.dot_maxtries");

const std::string kDotConnectTimeoutMsFlag(

        "persist.device_config.netd_native.dot_connect_timeout_ms");

const std::string kDotRevalidationThresholdFlag(

        "persist.device_config.netd_native.dot_revalidation_threshold");

const std::string kDotXportUnusableThresholdFlag(

        "persist.device_config.netd_native.dot_xport_unusable_threshold");

const std::string kDotQueryTimeoutMsFlag("persist.device_config.netd_native.dot_query_timeout_ms");

const std::string kDotValidationLatencyFactorFlag(

        "persist.device_config.netd_native.dot_validation_latency_factor");

const std::string kDotValidationLatencyOffsetMsFlag(

        "persist.device_config.netd_native.dot_validation_latency_offset_ms");

const std::string kDotQuickFallbackFlag("persist.device_config.netd_native.dot_quick_fallback");

const std::string kRetransIntervalFlag(

        "persist.device_config.netd_native.retransmission_time_interval");

const std::string kRetryCountFlag("persist.device_config.netd_native.retry_count");

const std::string kSortNameserversFlag("persist.device_config.netd_native.sort_nameservers");

const std::string kFlagPrefix("persist.device_config.netd_native.");

const std::string kDohEarlyDataFlag(kFlagPrefix + "doh_early_data");

const std::string kDohFlag(kFlagPrefix + "doh");

const std::string kDohIdleTimeoutFlag(kFlagPrefix + "doh_idle_timeout_ms");

const std::string kDohProbeTimeoutFlag(kFlagPrefix + "doh_probe_timeout_ms");

const std::string kDohQueryTimeoutFlag(kFlagPrefix + "doh_query_timeout_ms");

const std::string kDohSessionResumptionFlag(kFlagPrefix + "doh_session_resumption");

const std::string kDotAsyncHandshakeFlag(kFlagPrefix + "dot_async_handshake");

const std::string kDotConnectTimeoutMsFlag(kFlagPrefix + "dot_connect_timeout_ms");

const std::string kDotMaxretriesFlag(kFlagPrefix + "dot_maxtries");

const std::string kDotQueryTimeoutMsFlag(kFlagPrefix + "dot_query_timeout_ms");

const std::string kDotQuickFallbackFlag(kFlagPrefix + "dot_quick_fallback");

const std::string kDotRevalidationThresholdFlag(kFlagPrefix + "dot_revalidation_threshold");

const std::string kDotXportUnusableThresholdFlag(kFlagPrefix + "dot_xport_unusable_threshold");

const std::string kDotValidationLatencyFactorFlag(kFlagPrefix + "dot_validation_latency_factor");

const std::string kDotValidationLatencyOffsetMsFlag(kFlagPrefix +

                                                    "dot_validation_latency_offset_ms");

const std::string kRetransIntervalFlag(kFlagPrefix + "retransmission_time_interval");

const std::string kRetryCountFlag(kFlagPrefix + "retry_count");

const std::string kSortNameserversFlag(kFlagPrefix + "sort_nameservers");

static constexpr char kLocalHost[] = "localhost";

static constexpr char kLocalHostAddr[] = "127.0.0.1";