[net/dns] Instrument DnsConfigService to measure performance and failures.

net/dns/dns_config_service_posix_unittest.cc

Index: net/dns/dns_config_service_posix_unittest.cc
diff --git a/net/dns/dns_config_service_posix_unittest.cc b/net/dns/dns_config_service_posix_unittest.cc
index e1e23380f68cc72494679e22cc593911bfc96650..c4d7da74d7cb881a1c52daa17f4aa1d4e38d7681 100644
--- a/net/dns/dns_config_service_posix_unittest.cc
+++ b/net/dns/dns_config_service_posix_unittest.cc
@@ -30,7 +30,7 @@ const char* kNameserversIPv6[] = {
 // Fills in |res| with sane configuration.
 void InitializeResState(res_state res) {
   memset(res, 0, sizeof(*res));
-  res->options = RES_INIT | RES_ROTATE;
+  res->options = RES_INIT | RES_DEFAULT | RES_ROTATE;
   res->ndots = 2;
   res->retrans = 4;
   res->retry = 7;
@@ -124,7 +124,7 @@ TEST(DnsConfigServicePosixTest, ConvertResStateToDnsConfig) {
 
 TEST(DnsConfigServicePosixTest, RejectEmptyNameserver) {
   struct __res_state res = {};
-  res.options = RES_INIT;
+  res.options = RES_INIT | RES_DEFAULT;
   const char kDnsrch[] = "chromium.org";
   memcpy(res.defdname, kDnsrch, sizeof(kDnsrch));
   res.dnsrch[0] = res.defdname;