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

chrome/browser/background/background_contents_service.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 "chrome/browser/background/background_contents_service.h"
 
 #include "apps/app_load_service.h"
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/prefs/pref_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/background/background_contents_service_factory.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/image_loader.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/notifications/notification.h"
@@ skipping 657 matching lines @@
     bool user_gesture,
     bool* was_blocked) {
   Browser* browser = chrome::FindLastActiveWithProfile(
       Profile::FromBrowserContext(new_contents->GetBrowserContext()),
       chrome::GetActiveDesktop());
   if (browser) {
     chrome::AddWebContents(browser, NULL, new_contents, disposition,
                            initial_pos, user_gesture, was_blocked);
   }
 }