net: Cleanup class/struct forward declarations

net/disk_cache/simple/simple_entry_format.h

 // 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.
 
 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_
 
 #include <stdint.h>
 
 #include "net/base/net_export.h"
 
-namespace base {
-class Time;
-}
-
 namespace disk_cache {
 
 const uint64_t kSimpleInitialMagicNumber = UINT64_C(0xfcfb6d1ba7725c30);
 const uint64_t kSimpleFinalMagicNumber = UINT64_C(0xf4fa6f45970d41d8);
 const uint64_t kSimpleSparseRangeMagicNumber = UINT64_C(0xeb97bf016553676b);
 
 // A file containing stream 0 and stream 1 in the Simple cache consists of:
 //   - a SimpleFileHeader.
 //   - the key.
 //   - the data from stream 1.
@@ skipping 46 matching lines @@
 
   uint64_t sparse_range_magic_number;
   int64_t offset;
   int64_t length;
   uint32_t data_crc32;
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_