Modify ThreadChecker and NonThreadSafe so that their functionality is

net/disk_cache/block_files.h

 // Copyright (c) 2010 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.
 
 // See net/disk_cache/disk_cache.h for the public interface.
 
 #ifndef NET_DISK_CACHE_BLOCK_FILES_H__
 #define NET_DISK_CACHE_BLOCK_FILES_H__
 #pragma once
 
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
 #include "net/disk_cache/addr.h"
 #include "net/disk_cache/mapped_file.h"
 
-namespace base {
-class ThreadChecker;

[brettw, 2011/03/03 17:39:43]

It kind of sucks we lose the ability to forward declare this, especially in some
of these common files like ipc_channel.h. What if you make ThreadChecker derive
from the Impl one so it can still be forward declared?

-}
-
 namespace disk_cache {
 
 // This class handles the set of block-files open by the disk cache.
 class BlockFiles {
  public:
   explicit BlockFiles(const FilePath& path);
   ~BlockFiles();
 
   // Performs the object initialization. create_files indicates if the backing
   // files should be created or just open.
@@ skipping 61 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_ZeroSizeFile);
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_InvalidFile);
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_Stats);
 
   DISALLOW_COPY_AND_ASSIGN(BlockFiles);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BLOCK_FILES_H__