Use common code to set HttpNetworkSession::Param pointers.

net/url_request/url_request_context_builder.h

Index: net/url_request/url_request_context_builder.h
diff --git a/net/url_request/url_request_context_builder.h b/net/url_request/url_request_context_builder.h
index 724b9ffb83e195e2d0370bfd85a599b7bf5f4a91..4ff4b019e97bec974267a39964ff854978edad1d 100644
--- a/net/url_request/url_request_context_builder.h
+++ b/net/url_request/url_request_context_builder.h
@@ -26,6 +26,7 @@
 #include "net/base/net_export.h"
 #include "net/base/network_delegate.h"
 #include "net/dns/host_resolver.h"
+#include "net/http/http_network_session.h"
 #include "net/proxy/proxy_config_service.h"
 #include "net/proxy/proxy_service.h"
 #include "net/quic/quic_protocol.h"
@@ -89,6 +90,14 @@ class NET_EXPORT URLRequestContextBuilder {
   URLRequestContextBuilder();
   ~URLRequestContextBuilder();
 
+  // Extracts the component pointers required to construct an HttpNetworkSession
+  // and copies them into the Params used to create the session. This function
+  // should be used to ensure that a context and its associated
+  // HttpNetworkSession are consistent.
+  static void SetHttpNetworkSessionComponents(
+      const URLRequestContext* context,
+      HttpNetworkSession::Params* params);
+
   // These functions are mutually exclusive.  The ProxyConfigService, if
   // set, will be used to construct a ProxyService.
   void set_proxy_config_service(ProxyConfigService* proxy_config_service) {