Move data reduction proxy to Chrome-Proxy header for authentication

net/http/http_network_transaction.cc

Index: net/http/http_network_transaction.cc
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 32af2dd1844a8170be8615aa2701601e24ee0b63..0d8e4c917e11bd9954d2139d484917e73d76f987 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -465,6 +465,11 @@ void HttpNetworkTransaction::SetBeforeNetworkStartCallback(
   before_network_start_callback_ = callback;
 }
 
+void HttpNetworkTransaction::SetBeforeProxyHeadersSentCallback(
+    const BeforeProxyHeadersSentCallback& callback) {
+  before_proxy_headers_sent_callback_ = callback;
+}
+
 int HttpNetworkTransaction::ResumeNetworkStart() {
   DCHECK_EQ(next_state_, STATE_CREATE_STREAM);
   return DoLoop(OK);
@@ -879,6 +884,9 @@ void HttpNetworkTransaction::BuildRequestHeaders(bool using_proxy) {
     auth_controllers_[HttpAuth::AUTH_SERVER]->AddAuthorizationHeader(
         &request_headers_);
 
+  if (using_proxy && !before_proxy_headers_sent_callback_.is_null())
+    before_proxy_headers_sent_callback_.Run(&proxy_info_);
+
   request_headers_.MergeFrom(request_->extra_headers);
   response_.did_use_http_auth =
       request_headers_.HasHeader(HttpRequestHeaders::kAuthorization) ||