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

chrome/browser/signin/signin_manager.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/signin/signin_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/memory/ref_counted.h"
 #include "base/prefs/pref_service.h"
-#include "base/string_util.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time.h"
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/browser/signin/about_signin_internals.h"
 #include "chrome/browser/signin/about_signin_internals_factory.h"
 #include "chrome/browser/signin/signin_global_error.h"
 #include "chrome/browser/signin/signin_internals_util.h"
 #include "chrome/browser/signin/signin_manager_cookie_helper.h"
 #include "chrome/browser/signin/signin_manager_delegate.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
@@ skipping 672 matching lines @@
   }
 }
 
 void SigninManager::ProhibitSignout(bool prohibit_signout) {
   prohibit_signout_ = prohibit_signout;
 }
 
 bool SigninManager::IsSignoutProhibited() const {
   return prohibit_signout_;
 }