Step 2 in porting disk cache to using FilePath.

net/disk_cache/file.h

 // Copyright (c) 2006-2008 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 of the cache.
 
 #ifndef NET_DISK_CACHE_FILE_H_
 #define NET_DISK_CACHE_FILE_H_
 
 #include <string>
 
 #include "base/platform_file.h"
 #include "base/ref_counted.h"
 
+class FilePath;
+
 namespace disk_cache {
 
 // This interface is used to support asynchronous ReadData and WriteData calls.
 class FileIOCallback {
  public:
   // Notified of the actual number of bytes read or written. This value is
   // negative if an error occurred.
   virtual void OnFileIOComplete(int bytes_copied) = 0;
 
   virtual ~FileIOCallback() {}
 };
 
 // Simple wrapper around a file that allows asynchronous operations.
 class File : public base::RefCounted<File> {
   friend class base::RefCounted<File>;
  public:
   File() : init_(false), mixed_(false) {}
   // mixed_mode set to true enables regular synchronous operations for the file.
   explicit File(bool mixed_mode) : init_(false), mixed_(mixed_mode) {}
 
   // Initializes the object to use the passed in file instead of opening it with
   // the Init() call. No asynchronous operations can be performed with this
   // object.
   explicit File(base::PlatformFile file);
 
   // Initializes the object to point to a given file. The file must aready exist
   // on disk, and allow shared read and write.
-  bool Init(const std::wstring& name);
+  bool Init(const FilePath& name);
 
   // Returns the handle or file descriptor.
   base::PlatformFile platform_file() const;
 
   // Returns true if the file was opened properly.
   bool IsValid() const;
 
   // Performs synchronous IO.
   bool Read(void* buffer, size_t buffer_len, size_t offset);
   bool Write(const void* buffer, size_t buffer_len, size_t offset);
@@ skipping 30 matching lines @@
   bool mixed_;
   base::PlatformFile platform_file_;  // Regular, asynchronous IO handle.
   base::PlatformFile sync_platform_file_;  // Synchronous IO handle.
 
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_FILE_H_