[HttpCache::Transaction] Force states to set the next state

net/http/http_cache_transaction.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 declares HttpCache::Transaction, a private class of HttpCache so
 // it should only be included by http_cache.cc
 
 #ifndef NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 #define NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 
@@ skipping 161 matching lines @@
   // Helper struct to pair a header name with its value, for
   // headers used to validate cache entries.
   struct ValidationHeaders {
     ValidationHeaders() : initialized(false) {}
 
     std::string values[kNumValidationHeaders];
     bool initialized;
   };
 
   enum State {
+    STATE_UNSET,
+
     // Normally, states are traversed in approximately this order.
     STATE_NONE,
     STATE_GET_BACKEND,
     STATE_GET_BACKEND_COMPLETE,
     STATE_INIT_ENTRY,
     STATE_OPEN_ENTRY,
     STATE_OPEN_ENTRY_COMPLETE,
     STATE_DOOM_ENTRY,
     STATE_DOOM_ENTRY_COMPLETE,
     STATE_CREATE_ENTRY,
@@ skipping 315 matching lines @@
   BeforeHeadersSentCallback before_headers_sent_callback_;
 
   base::WeakPtrFactory<Transaction> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Transaction);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_TRANSACTION_H_