Retry upon 421 status code without IP pooling.

net/base/net_error_list.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file intentionally does not have header guards, it's included
 // inside a macro to generate enum values.
 
 // This file contains the list of network errors.
 
 //
@@ skipping 684 matching lines @@
 NET_ERROR(INVALID_HTTP_RESPONSE, -370)
 
 // Initializing content decoding failed.
 NET_ERROR(CONTENT_DECODING_INIT_FAILED, -371)
 
 // Received HTTP/2 RST_STREAM frame with NO_ERROR error code.  This error should
 // be handled internally by HTTP/2 code, and should not make it above the
 // SpdyStream layer.
 NET_ERROR(SPDY_RST_STREAM_NO_ERROR_RECEIVED, -372)
 
+// Received HTTP status code 421 Misdirected Request (RFC7540 Section 9.1.2).
+// The client MAY retry the request over a different connection.
+NET_ERROR(MISDIRECTED_REQUEST, -373)
+
 // The cache does not have the requested entry.
 NET_ERROR(CACHE_MISS, -400)
 
 // Unable to read from the disk cache.
 NET_ERROR(CACHE_READ_FAILURE, -401)
 
 // Unable to write to the disk cache.
 NET_ERROR(CACHE_WRITE_FAILURE, -402)
 
 // The operation is not supported for this entry.
@@ skipping 140 matching lines @@
 NET_ERROR(DNS_TIMED_OUT, -803)
 
 // The entry was not found in cache, for cache-only lookups.
 NET_ERROR(DNS_CACHE_MISS, -804)
 
 // Suffix search list rules prevent resolution of the given host name.
 NET_ERROR(DNS_SEARCH_EMPTY, -805)
 
 // Failed to sort addresses according to RFC3484.
 NET_ERROR(DNS_SORT_ERROR, -806)