**STILLBAKING** Decouple disk cache tests from backends.

net/disk_cache/cache_creator.cc

 // 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.
 
 #include "base/files/file_path.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/stringprintf.h"
 #include "net/base/cache_type.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/cache_util.h"
@@ skipping 141 matching lines @@
 namespace disk_cache {
 
 int CreateCacheBackend(net::CacheType type,
                        net::BackendType backend_type,
                        const base::FilePath& path,
                        int max_bytes,
                        bool force, base::MessageLoopProxy* thread,
                        net::NetLog* net_log, scoped_ptr<Backend>* backend,
                        const net::CompletionCallback& callback) {
   DCHECK(!callback.is_null());
-  if (type == net::MEMORY_CACHE) {
+  if (backend_type == net::CACHE_BACKEND_MEMORY || type == net::MEMORY_CACHE) {
     *backend = disk_cache::MemBackendImpl::CreateBackend(max_bytes, net_log);
     return *backend ? net::OK : net::ERR_FAILED;
   }
   DCHECK(thread);
   CacheCreator* creator = new CacheCreator(path, force, max_bytes, type,
                                            backend_type, 0,
                                            thread, net_log, backend, callback);
   return creator->Run();
 }
 
 }  // namespace disk_cache