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

net/dns/dns_config_service.h

Index: net/dns/dns_config_service.h
diff --git a/net/dns/dns_config_service.h b/net/dns/dns_config_service.h
index 4b77b68c51db353c8f23365aeb99bb994bb9f1b0..410a6d89063f396ac905b5497e0086ca60de2f6b 100644
--- a/net/dns/dns_config_service.h
+++ b/net/dns/dns_config_service.h
@@ -138,6 +138,9 @@ class NET_EXPORT_PRIVATE DnsConfigService
   // True if the last config sent was empty (instead of |dns_config_|).
   bool last_sent_empty_;
 
+  base::TimeTicks last_invalidate_config_time_;
+  base::TimeTicks last_invalidate_hosts_time_;

[mmenke, 2012/06/18 17:19:50]

This it's worth a comment that these will be set when the config and hosts files
are first read.

+
   // Started in Invalidate*, cleared in On*Read.
   base::OneShotTimer<DnsConfigService> timer_;