Initialize the simple cache backend at runtime.

net/disk_cache/simple/simple_backend_impl.cc

 // Copyright (c) 2013 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/disk_cache/simple/simple_backend_impl.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/location.h"
@@ skipping 24 matching lines @@
   callback.Run(result);
 }
 
 }  // namespace
 
 namespace disk_cache {
 
 // static
 int SimpleBackendImpl::CreateBackend(
     const FilePath& full_path,
-    bool force,
     int max_bytes,
     net::CacheType type,
     uint32 flags,
     scoped_refptr<base::TaskRunner> cache_thread,
     net::NetLog* net_log,
     Backend** backend,
     const CompletionCallback& callback) {
   // TODO(gavinp): Use the |net_log|.
   DCHECK_EQ(net::DISK_CACHE, type);
   FilePath simple_cache_path =
@@ skipping 115 matching lines @@
                         base::Bind(callback, result));
   } else {
     io_thread->PostTask(FROM_HERE,
                         base::Bind(
                             &DeleteBackendImpl,
                             backend, callback, result));
   }
 }
 
 }  // namespace disk_cache