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

chrome/browser/browsing_data/cookies_tree_model.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/browsing_data/cookies_tree_model.h"
 
 #include <algorithm>
 #include <functional>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/memory/linked_ptr.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/browsing_data/browsing_data_cookie_helper.h"
 #include "chrome/browser/browsing_data/browsing_data_flash_lso_helper.h"
 #include "chrome/browser/browsing_data/browsing_data_server_bound_cert_helper.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_special_storage_policy.h"
 #include "content/public/common/url_constants.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
@@ skipping 1304 matching lines @@
 
 void CookiesTreeModel::NotifyObserverEndBatch() {
   // Only notify the observers if this is the outermost call to EndBatch() if
   // called in a nested manner.
   if (--batch_update_ == 0) {
     FOR_EACH_OBSERVER(Observer,
                       cookies_observer_list_,
                       TreeModelEndBatch(this));
   }
 }