Make the proxy server HostPortPair available in document_state so that

content/public/common/resource_response_info.h

Index: content/public/common/resource_response_info.h
diff --git a/content/public/common/resource_response_info.h b/content/public/common/resource_response_info.h
index 530952c2d401d27cd74539f75b997b3a3f5741fa..053182e63cb65e6409f92fc14a3000092261b5bd 100644
--- a/content/public/common/resource_response_info.h
+++ b/content/public/common/resource_response_info.h
@@ -94,6 +94,9 @@ struct ResourceResponseInfo {
   // Note: we cannot tell if a transparent proxy may have been involved.
   bool was_fetched_via_proxy;
 
+  // Remote address of the proxy server used for this resource, if one was used.
+  net::HostPortPair proxy_server;

[Charlie Reis, 2014/10/30 18:05:32]

It wasn't clear to me whether we need both this and |was_fetched_via_proxy|. 
Looks like they're grouped together with a comment in HttpResponseInfo.  Can we
do something similar here?

[jeremyim, 2014/10/30 19:00:36]

Done.

+
   // NPN protocol negotiated with the server.
   std::string npn_negotiated_protocol;