Use a direct include of strings headers in chrome/browser/d*/.

chrome/browser/download/download_browsertest.cc

 // 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.
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_service.h"
 #include "base/stl_util.h"
-#include "base/stringprintf.h"
 #include "base/strings/string_split.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/test/test_file_util.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/common/cancelable_request.h"
 #include "chrome/browser/download/chrome_download_manager_delegate.h"
 #include "chrome/browser/download/download_crx_util.h"
 #include "chrome/browser/download/download_history.h"
 #include "chrome/browser/download/download_item_model.h"
@@ skipping 2936 matching lines @@
   EXPECT_EQ(dir.value(), off_prefs->SaveFilePath().value());
 
   off_prefs->SetSaveFilePath(dir.AppendASCII("off"));
   EXPECT_EQ(dir.value(), on_prefs->SaveFilePath().value());
   EXPECT_EQ(dir.AppendASCII("off").value(), off_prefs->SaveFilePath().value());
 
   on_prefs->SetSaveFilePath(dir.AppendASCII("on"));
   EXPECT_EQ(dir.AppendASCII("on").value(), on_prefs->SaveFilePath().value());
   EXPECT_EQ(dir.AppendASCII("off").value(), off_prefs->SaveFilePath().value());
 }