Add DataReductionProxy IPC to determine if the Data Reduction Proxy was used.

content/public/renderer/document_state.h

Index: content/public/renderer/document_state.h
diff --git a/content/public/renderer/document_state.h b/content/public/renderer/document_state.h
index d388a8a979ef0dcdc695ac86221ce470409ffce7..bd97cdaf55727d8c9b9cfa99665419f368edf455 100644
--- a/content/public/renderer/document_state.h
+++ b/content/public/renderer/document_state.h
@@ -161,7 +161,7 @@ class CONTENT_EXPORT DocumentState
     was_fetched_via_proxy_ = value;
   }
 
-  net::HostPortPair proxy_server() const { return proxy_server_; }
+  net::HostPortPair& proxy_server() { return proxy_server_; }

[Charlie Reis, 2015/02/27 22:07:42]

Why do you need this change?

[jeremyim, 2015/02/27 22:17:01]

I can put it in a separate CL; I noticed that we weren't returning it via ref,
which means that we might be performing a copy when returning the information to
callers.

[Charlie Reis, 2015/02/27 22:37:36]

Style guide is against passing around non-const references.  Please keep the
existing const and return a const ref if you want to avoid the copy.

[jeremyim, 2015/02/27 22:50:55]

Done.

   void set_proxy_server(net::HostPortPair proxy_server) {
     proxy_server_ = proxy_server;
   }