Cleanup usage of scoped_ptr<> in remoting for C++11

remoting/protocol/content_description.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 "remoting/protocol/content_description.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "remoting/base/constants.h"
 #include "remoting/protocol/authenticator.h"
@@ skipping 196 matching lines @@
       configs->push_back(ChannelConfig::None());
   }
   return true;
 }
 
 // static
 scoped_ptr<ContentDescription> ContentDescription::ParseXml(
     const XmlElement* element) {
   if (element->Name() != QName(kChromotingXmlNamespace, kDescriptionTag)) {
     LOG(ERROR) << "Invalid description: " << element->Str();
-    return scoped_ptr<ContentDescription>();
+    return nullptr;
   }
   scoped_ptr<CandidateSessionConfig> config(
       CandidateSessionConfig::CreateEmpty());
   if (!ParseChannelConfigs(element, kControlTag, false, false,
                            config->mutable_control_configs()) ||
       !ParseChannelConfigs(element, kEventTag, false, false,
                            config->mutable_event_configs()) ||
       !ParseChannelConfigs(element, kVideoTag, true, false,
                            config->mutable_video_configs()) ||
       !ParseChannelConfigs(element, kAudioTag, true, true,
                            config->mutable_audio_configs())) {
-    return scoped_ptr<ContentDescription>();
+    return nullptr;
   }
 
   scoped_ptr<XmlElement> authenticator_message;
   const XmlElement* child = Authenticator::FindAuthenticatorMessage(element);
   if (child)
     authenticator_message.reset(new XmlElement(*child));
 
   return scoped_ptr<ContentDescription>(
       new ContentDescription(config.Pass(), authenticator_message.Pass()));
 }
 
 }  // namespace protocol
 }  // namespace remoting