Add client for background testing of HTTP pipelining.

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.
 
 // This file contains the list of network errors.
 
 //
@@ skipping 507 matching lines @@
 // The HTTP response contained multiple Location headers.
 NET_ERROR(RESPONSE_HEADERS_MULTIPLE_LOCATION, -350)
 
 // SPDY server refused the stream. Client should retry. This should never be a
 // user-visible error.
 NET_ERROR(SPDY_SERVER_REFUSED_STREAM, -351)
 
 // SPDY server didn't respond to the PING message.
 NET_ERROR(SPDY_PING_FAILED, -352)
 
+// The request couldn't be completed on an HTTP pipeline. Client should retry.
+NET_ERROR(PIPELINE_EVICTION, -353)
+
 // 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 109 matching lines @@
 //     kind of query.
 // 5 - Refused - The name server refuses to perform the specified
 //     operation for policy reasons.
 NET_ERROR(DNS_SERVER_FAILED, -802)
 
 // DNS transaction timed out.
 NET_ERROR(DNS_TIMED_OUT, -803)
 
 // The entry was not found in cache, for cache-only lookups.
 NET_ERROR(DNS_CACHE_MISS, -804)
-
-// FIXME: Take the next number.
-NET_ERROR(PIPELINE_EVICTION, -900)