Retry upon 421 status code without IP pooling.

net/http/http_stream_factory_impl_job_controller.h

Index: net/http/http_stream_factory_impl_job_controller.h
diff --git a/net/http/http_stream_factory_impl_job_controller.h b/net/http/http_stream_factory_impl_job_controller.h
index c57ecd4769ef6bad7a9ccf585d57aa3c82a32ab0..c5e0bb5440bb44b6e47ff312ffaef2bd6f84c358 100644
--- a/net/http/http_stream_factory_impl_job_controller.h
+++ b/net/http/http_stream_factory_impl_job_controller.h
@@ -24,7 +24,8 @@ class HttpStreamFactoryImpl::JobController
                 HttpNetworkSession* session,
                 JobFactory* job_factory,
                 const HttpRequestInfo& request_info,
-                bool is_preconnect);
+                bool is_preconnect,
+                bool enable_ip_based_pooling);
 
   ~JobController() override;
 
@@ -288,6 +289,10 @@ class HttpStreamFactoryImpl::JobController
   // True if this JobController is used to preconnect streams.
   const bool is_preconnect_;
 
+  // Enable pooling to a SpdySession with matching IP and certificate even if
+  // the SpdySessionKey is different.
+  const bool enable_ip_based_pooling_;
+
   // |main_job_| is a job waiting to see if |alternative_job_| can reuse a
   // connection. If |alternative_job_| is unable to do so, |this| will notify
   // |main_job_| to proceed and then race the two jobs.