Use a direct include of strings headers in chrome/browser/ui/cocoa/.

chrome/browser/ui/cocoa/toolbar/toolbar_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/toolbar/toolbar_controller.h"
 
 #include <algorithm>
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/memory/singleton.h"
 #include "base/prefs/pref_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/command_updater.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/search.h"
@@ skipping 807 matching lines @@
 - (void)hideDropURLsIndicatorInView:(NSView*)view {
   // Do nothing.
 }
 
 // (URLDropTargetController protocol)
 - (BOOL)isUnsupportedDropData:(id<NSDraggingInfo>)info {
   return drag_util::IsUnsupportedDropData(profile_, info);
 }
 
 @end