base: Update the include paths of base/string_piece.h to its new location.

base/files/file_path.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.
 
 // FilePath is a container for pathnames stored in a platform's native string
 // type, providing containers for manipulation in according with the
 // platform's conventions for pathnames.  It supports the following path
 // types:
 //
 //                   POSIX            Windows
@@ skipping 92 matching lines @@
 #define BASE_FILES_FILE_PATH_H_
 
 #include <stddef.h>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
 #include "base/hash_tables.h"
 #include "base/string16.h"
-#include "base/string_piece.h"  // For implicit conversions.
+#include "base/strings/string_piece.h"  // For implicit conversions.
 #include "build/build_config.h"
 
 // Windows-style drive letter support and pathname separator characters can be
 // enabled and disabled independently, to aid testing.  These #defines are
 // here so that the same setting can be used in both the implementation and
 // in the unit test.
 #if defined(OS_WIN)
 #define FILE_PATH_USES_DRIVE_LETTERS
 #define FILE_PATH_USES_WIN_SEPARATORS
 #endif  // OS_WIN
@@ skipping 309 matching lines @@
 
 inline size_t hash_value(const base::FilePath& f) {
   return hash_value(f.value());
 }
 
 #endif  // COMPILER
 
 }  // namespace BASE_HASH_NAMESPACE
 
 #endif  // BASE_FILES_FILE_PATH_H_