Use a direct include of strings headers in chrome/browser/ui/webui/, part 1.

chrome/browser/ui/webui/extensions/extension_settings_handler.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/ui/webui/extensions/extension_settings_handler.h"
 
 #include "apps/app_load_service.h"
 #include "apps/app_restore_service.h"
 #include "apps/saved_files_service.h"
 #include "base/auto_reset.h"
 #include "base/base64.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
-#include "base/string_util.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/extensions/api/extension_action/extension_action_api.h"
 #include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/extension_action_manager.h"
 #include "chrome/browser/extensions/extension_disabled_ui.h"
 #include "chrome/browser/extensions/extension_error_reporter.h"
@@ skipping 1034 matching lines @@
     std::vector<std::string> requirement_errors) {
   if (requirement_errors.empty()) {
     extension_service_->EnableExtension(extension_id);
   } else {
     ExtensionErrorReporter::GetInstance()->ReportError(
         UTF8ToUTF16(JoinString(requirement_errors, ' ')),
         true /* be noisy */);
   }
   requirements_checker_.reset();
 }