Use RevocableStore to isolate the http cache from its transactions....

net/http/http_cache_unittest.cc

 // Copyright (c) 2006-2008 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.
 
 #include "net/http/http_cache.h"
 
 #include "base/hash_tables.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "net/base/net_errors.h"
@@ skipping 1070 matching lines @@
 
   scoped_ptr<net::HttpTransaction> trans(
       cache.http_cache()->CreateTransaction());
   ASSERT_TRUE(trans.get());
 
   int rv = trans->Start(&request, &callback);
   if (rv == net::ERR_IO_PENDING)
     rv = callback.WaitForResult();
   ASSERT_EQ(net::ERR_CACHE_MISS, rv);
 }
+
+// Ensure that we don't crash by if left-behind transactions.
+TEST(HttpCache, OutlivedTransactions) {
+  MockHttpCache* cache = new MockHttpCache;
+
+  net::HttpTransaction* trans = cache->http_cache()->CreateTransaction();
+  delete cache; 
+  delete trans;
+}