Move string files in base/ to the string subdirectory.

base/strings/string_util_posix.h

 // Copyright (c) 2011 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_STRING_UTIL_POSIX_H_
-#define BASE_STRING_UTIL_POSIX_H_
+#ifndef BASE_STRINGS_STRING_UTIL_POSIX_H_
+#define BASE_STRINGS_STRING_UTIL_POSIX_H_
 
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 #include <wchar.h>
 
 #include "base/logging.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 
 namespace base {
 
 // Chromium code style is to not use malloc'd strings; this is only for use
 // for interaction with APIs that require it.
 inline char* strdup(const char* str) {
   return ::strdup(str);
 }
 
 inline int strcasecmp(const char* string1, const char* string2) {
@@ skipping 18 matching lines @@
 }
 
 inline int vswprintf(wchar_t* buffer, size_t size,
                      const wchar_t* format, va_list arguments) {
   DCHECK(IsWprintfFormatPortable(format));
   return ::vswprintf(buffer, size, format, arguments);
 }
 
 }  // namespace base
 
-#endif  // BASE_STRING_UTIL_POSIX_H_
+#endif  // BASE_STRINGS_STRING_UTIL_POSIX_H_