Fix IWYU in base/files/file.h

net/disk_cache/flash/storage.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_DISK_CACHE_FLASH_STORAGE_H_
 #define NET_DISK_CACHE_FLASH_STORAGE_H_
 
 #include "base/basictypes.h"
 #include "base/files/file.h"
+#include "base/files/file_path.h"
 #include "net/base/net_export.h"
 
 namespace disk_cache {
 
 class NET_EXPORT_PRIVATE Storage {
  public:
   Storage(const base::FilePath& path, int32 size);
   bool Init();
   ~Storage();
 
   int32 size() const { return size_; }
 
   bool Read(void* buffer, int32 size, int32 offset);
   bool Write(const void* buffer, int32 size, int32 offset);
 
  private:
   base::FilePath path_;
   int32 size_;
   base::File file_;
 
   DISALLOW_COPY_AND_ASSIGN(Storage);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_FLASH_STORAGE_H_