Refactor prefs.js for MD-Settings

chrome/browser/extensions/api/settings_private/settings_private_delegate.cc

 // Copyright 2015 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/api/settings_private/settings_private_delegate.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
@@ skipping 31 matching lines @@
   const TypedPrefMap& keys = prefs_util_->GetWhitelistedKeys();
   for (const auto& it : keys) {
     scoped_ptr<base::Value> pref = GetPref(it.first);
     if (!pref->IsType(base::Value::TYPE_NULL))
       prefs->Append(pref.release());
   }
 
   return prefs.Pass();
 }
 
-bool SettingsPrivateDelegate::SetPref(const std::string& pref_name,
-                                      const base::Value* value) {
+PrefsUtil::SetPrefResult SettingsPrivateDelegate::SetPref(
+    const std::string& pref_name, const base::Value* value) {
   return prefs_util_->SetPref(pref_name, value);
 }
 
 }  // namespace extensions