net: Cleanup class/struct forward declarations

net/extras/sqlite/sqlite_persistent_cookie_store.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.
 
 #ifndef NET_EXTRAS_SQLITE_SQLITE_PERSISTENT_COOKIE_STORE_H_
 #define NET_EXTRAS_SQLITE_SQLITE_PERSISTENT_COOKIE_STORE_H_
 
 #include <list>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "net/cookies/cookie_monster.h"
 
-class Task;
-
 namespace base {
 class FilePath;
 class SequencedTaskRunner;
 }  // namespace base
 
 namespace net {
 class CanonicalCookie;
 class CookieCryptoDelegate;
 
 // Implements the PersistentCookieStore interface in terms of a SQLite database.
@@ skipping 42 matching lines @@
   class Backend;
 
   scoped_refptr<Backend> backend_;
 
   DISALLOW_COPY_AND_ASSIGN(SQLitePersistentCookieStore);
 };
 
 }  // namespace net
 
 #endif  // NET_EXTRAS_SQLITE_SQLITE_PERSISTENT_COOKIE_STORE_H_