Fix IWYU in base/files/file.h

base/files/file.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 BASE_FILES_FILE_H_
 #define BASE_FILES_FILE_H_
 
 #include "build/build_config.h"
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
-#include <string>
-
 #include "base/base_export.h"
 #include "base/basictypes.h"
-#include "base/files/file_path.h"
 #include "base/move.h"
 #include "base/time/time.h"
 
 #if defined(OS_WIN)
 #include "base/win/scoped_handle.h"
 #endif
 
 namespace base {
 
+class FilePath;
+
 #if defined(OS_WIN)
 typedef HANDLE PlatformFile;
 #elif defined(OS_POSIX)
 typedef int PlatformFile;
 #endif
 
 
 // Thin wrapper around an OS-level file.
 // Note that this class does not provide any support for asynchronous IO, other
 // than the ability to create asynchronous handles on Windows.
@@ skipping 244 matching lines @@
 #endif
 
   Error error_details_;
   bool created_;
   bool async_;
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_H_