Http cache: Implement a timeout for the cache lock.

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 627 matching lines @@
 // returned from attempts to read from the cache. It is an internal error,
 // returned by the SimpleCache backend, but not by any URLRequest methods
 // or members.
 NET_ERROR(CACHE_CHECKSUM_READ_FAILURE, -407)
 
 // The cache found an entry with an invalid checksum. This can be returned from
 // attempts to read from the cache. It is an internal error, returned by the
 // SimpleCache backend, but not by any URLRequest methods or members.
 NET_ERROR(CACHE_CHECKSUM_MISMATCH, -408)
 
+// Internal error code for the HTTP cache. The cache lock timeout has fired.
+NET_ERROR(CACHE_LOCK_TIMEOUT, -409)
+
 // The server's response was insecure (e.g. there was a cert error).
 NET_ERROR(INSECURE_RESPONSE, -501)
 
 // The server responded to a <keygen> with a generated client cert that we
 // don't have the matching private key for.
 NET_ERROR(NO_PRIVATE_KEY_FOR_CERT, -502)
 
 // An error adding to the OS certificate database (e.g. OS X Keychain).
 NET_ERROR(ADD_USER_CERT_FAILED, -503)
 
@@ skipping 97 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)