Use a direct include of strings headers in chrome/browser/extensions/, part 4.

chrome/browser/extensions/external_provider_impl.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/extensions/external_provider_impl.h"
 
 #include <set>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
 #include "base/metrics/field_trial.h"
 #include "base/path_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/values.h"
 #include "base/version.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/external_component_loader.h"
 #include "chrome/browser/extensions/external_policy_loader.h"
 #include "chrome/browser/extensions/external_pref_loader.h"
 #include "chrome/browser/extensions/external_provider_interface.h"
@@ skipping 463 matching lines @@
         new ExternalProviderImpl(
             service,
             new ExternalComponentLoader(),
             profile,
             Manifest::INVALID_LOCATION,
             Manifest::EXTERNAL_POLICY_DOWNLOAD,
             Extension::FROM_WEBSTORE | Extension::WAS_INSTALLED_BY_DEFAULT)));
 }
 
 }  // namespace extensions