Use a direct include of strings headers in testing/, third_party/, tools/.

testing/android/native_test_util.cc

 // Copyright (c) 2013 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 "testing/android/native_test_util.h"
 
 #include <android/log.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
-#include "base/string_util.h"
 #include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
 
 namespace {
 
 const char kLogTag[] = "chromium";
 
 void AndroidLogError(const char* format, ...) {
   va_list args;
   va_start(args, format);
   __android_log_vprint(ANDROID_LOG_ERROR, kLogTag, format, args);
   va_end(args);
@@ skipping 52 matching lines @@
   for (int i = 0; i < argc; ++i) {
     (*argv)[i] = const_cast<char*>(args[i].c_str());
   }
   (*argv)[argc] = NULL;  // argv must be NULL terminated.
 
   return argc;
 }
 
 }  // namespace native_test_util
 }  // namespace testing