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

base/strings/sys_string_conversions_win.cc

 // 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.
 
 #include "base/strings/sys_string_conversions.h"
 
 #include <windows.h>
 
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 
 namespace base {
 
 // Do not assert in this function since it is used by the asssertion code!
 std::string SysWideToUTF8(const std::wstring& wide) {
   return SysWideToMultiByte(wide, CP_UTF8);
 }
 
 // Do not assert in this function since it is used by the asssertion code!
 std::wstring SysUTF8ToWide(const StringPiece& utf8) {
@@ skipping 41 matching lines @@
 
   std::string mb;
   mb.resize(charcount);
   WideCharToMultiByte(code_page, 0, wide.data(), wide_length,
                       &mb[0], charcount, NULL, NULL);
 
   return mb;
 }
 
 }  // namespace base