Basic HTTP pipelining support

net/http/http_network_session.h

Index: net/http/http_network_session.h
diff --git a/net/http/http_network_session.h b/net/http/http_network_session.h
index f7da9218aa7e5d1eaed03ed493ae945c2c526d75..4829bce52843060ab33239b40b59ac8ac0c720fa 100644
--- a/net/http/http_network_session.h
+++ b/net/http/http_network_session.h
@@ -15,6 +15,7 @@
 #include "net/base/ssl_client_auth_cache.h"
 #include "net/http/http_alternate_protocols.h"
 #include "net/http/http_auth_cache.h"
+#include "net/http/http_pipelined_host_pool.h"
 #include "net/http/http_stream_factory.h"
 #include "net/socket/client_socket_pool_manager.h"
 #include "net/spdy/spdy_session_pool.h"
@@ -112,6 +113,9 @@ class NET_API HttpNetworkSession
   ProxyService* proxy_service() { return proxy_service_; }
   SSLConfigService* ssl_config_service() { return ssl_config_service_; }
   SpdySessionPool* spdy_session_pool() { return &spdy_session_pool_; }
+  HttpPipelinedHostPool* http_pipelined_host_pool() {
+    return &http_pipelined_host_pool_;
+  }
   HttpAuthHandlerFactory* http_auth_handler_factory() {
     return http_auth_handler_factory_;
   }
@@ -159,6 +163,7 @@ class NET_API HttpNetworkSession
   ClientSocketPoolManager socket_pool_manager_;
   SpdySessionPool spdy_session_pool_;
   scoped_ptr<HttpStreamFactory> http_stream_factory_;
+  HttpPipelinedHostPool http_pipelined_host_pool_;
   std::set<HttpResponseBodyDrainer*> response_drainers_;
 };