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

chrome/browser/download/download_util.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.
 //
 // Download utility implementation
 
 #define _USE_MATH_DEFINES  // For VC++ to get M_PI. This has to be first.
 
 #include "chrome/browser/download/download_util.h"
 
 #include <cmath>
 #include <string>
 
 #include "base/file_util.h"
 #include "base/i18n/rtl.h"
 #include "base/i18n/time_formatting.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/value_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/download/download_extensions.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_notification_types.h"
@@ skipping 451 matching lines @@
   UMA_HISTOGRAM_ENUMERATION(
       "Download.CountsChrome", type, CHROME_DOWNLOAD_COUNT_TYPES_LAST_ENTRY);
 }
 
 void RecordDownloadSource(ChromeDownloadSource source) {
   UMA_HISTOGRAM_ENUMERATION(
       "Download.SourcesChrome", source, CHROME_DOWNLOAD_SOURCE_LAST_ENTRY);
 }
 
 }  // namespace download_util