Use a direct include of strings headers in x/.

chrome/browser/ui/views/download/download_item_view.h

 // 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.
 //
 // A ChromeView that implements one download on the Download shelf.
 // Each DownloadItemView contains an application icon, a text label
 // indicating the download's file name, a text label indicating the
 // download's status (such as the number of bytes downloaded so far)
 // and a button for canceling an in progress download, or opening
 // the completed download.
 //
 // The DownloadItemView lives in the Browser, and has a corresponding
 // DownloadController that receives / writes data which lives in the
 // Renderer.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_H__
 #define CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_H__
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/time.h"
 #include "base/timer.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/icon_manager.h"
 #include "chrome/common/cancelable_task_tracker.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "ui/base/animation/animation_delegate.h"
 #include "ui/gfx/font.h"
 #include "ui/views/context_menu_controller.h"
@@ skipping 288 matching lines @@
 
   // The icon loaded in the download shelf is based on the file path of the
   // item.  Store the path used, so that we can detect a change in the path
   // and reload the icon.
   base::FilePath last_download_item_path_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_H__