Use a direct include of strings headers in chrome/installer/, part 2.

chrome/installer/util/master_preferences.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/installer/util/master_preferences.h"
 
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/path_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "chrome/common/env_vars.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/installer/util/master_preferences_constants.h"
 #include "chrome/installer/util/util_constants.h"
 
 namespace {
 
 const char kFirstRunTabs[] = "first_run_tabs";
 
 base::LazyInstance<installer::MasterPreferences> g_master_preferences =
@@ skipping 291 matching lines @@
   master_dictionary_->GetString(prefs::kVariationsSeed, &variations_seed);
   return variations_seed;
 }
 
 // static
 const MasterPreferences& MasterPreferences::ForCurrentProcess() {
   return g_master_preferences.Get();
 }
 
 }  // namespace installer