Add embedder-specific headers to HTTP CONNECT tunnel request

net/socket/client_socket_pool_manager_impl.cc

Index: net/socket/client_socket_pool_manager_impl.cc
diff --git a/net/socket/client_socket_pool_manager_impl.cc b/net/socket/client_socket_pool_manager_impl.cc
index 083dfb061783bdf07337a5f96ec7bd1a77d5bbc7..3980981ca4e949dc46c03814c8c75c24d4e820ee 100644
--- a/net/socket/client_socket_pool_manager_impl.cc
+++ b/net/socket/client_socket_pool_manager_impl.cc
@@ -4,6 +4,7 @@
 
 #include "net/socket/client_socket_pool_manager_impl.h"
 
+#include "base/callback.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "net/http/http_network_session.h"
@@ -46,6 +47,8 @@ ClientSocketPoolManagerImpl::ClientSocketPoolManagerImpl(
     ProxyService* proxy_service,
     SSLConfigService* ssl_config_service,
     bool enable_ssl_connect_job_waiting,
+    const base::Callback<void(const HostPortPair&, HttpRequestHeaders*)>&
+        before_proxy_tunnel_request_callback,
     HttpNetworkSession::SocketPoolType pool_type)
     : net_log_(net_log),
       socket_factory_(socket_factory),
@@ -98,7 +101,9 @@ ClientSocketPoolManagerImpl::ClientSocketPoolManagerImpl(
       transport_for_https_proxy_pool_histograms_("TCPforHTTPSProxy"),
       ssl_for_https_proxy_pool_histograms_("SSLforHTTPSProxy"),
       http_proxy_pool_histograms_("HTTPProxy"),
-      ssl_socket_pool_for_proxies_histograms_("SSLForProxies") {
+      ssl_socket_pool_for_proxies_histograms_("SSLForProxies"),
+      before_proxy_tunnel_request_callback_(
+          before_proxy_tunnel_request_callback) {
   CertDatabase::GetInstance()->AddObserver(this);
 }
 
@@ -324,6 +329,7 @@ ClientSocketPoolManagerImpl::GetSocketPoolForHTTPProxy(
                   host_resolver_,
                   tcp_http_ret.first->second,
                   ssl_https_ret.first->second,
+                  before_proxy_tunnel_request_callback_,
                   net_log_)));
 
   return ret.first->second;