Domain Reliability: Add was_proxied field to beacons.

components/domain_reliability/beacon.h

Index: components/domain_reliability/beacon.h
diff --git a/components/domain_reliability/beacon.h b/components/domain_reliability/beacon.h
index cb5ed8c5081e8de22611ac73a596272b91658017..aba7bf9503b15b49e86d7c32a196d00b8c3c941e 100644
--- a/components/domain_reliability/beacon.h
+++ b/components/domain_reliability/beacon.h
@@ -39,6 +39,9 @@ struct DOMAIN_RELIABILITY_EXPORT DomainReliabilityBeacon {
   int chrome_error;
   // IP address of the server the request went to.
   std::string server_ip;
+  // Whether the request went through a proxy. If true, |server_ip| will be
+  // empty.
+  bool was_proxied;
   // Protocol used to make the request.
   std::string protocol;
   // HTTP response code returned by the server, or -1 if none was received.