Remove some linked_ptr c/b/extension

chrome/browser/extensions/api/mdns/dns_sd_registry.cc

 // Copyright 2013 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/mdns/dns_sd_registry.h"
 
 #include <utility>
 
+#include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
 #include "chrome/browser/extensions/api/mdns/dns_sd_device_lister.h"
 #include "chrome/browser/local_discovery/service_discovery_shared_client.h"
 #include "chrome/common/features.h"
 
 using local_discovery::ServiceDiscoveryClient;
 using local_discovery::ServiceDiscoverySharedClient;
 
 namespace extensions {
 
@@ skipping 134 matching lines @@
   if (IsRegistered(service_type)) {
     service_data_map_[service_type]->ListenerAdded();
     DispatchApiEvent(service_type);
     return;
   }
 
   std::unique_ptr<DnsSdDeviceLister> dns_sd_device_lister(
       CreateDnsSdDeviceLister(this, service_type,
                               service_discovery_client_.get()));
   dns_sd_device_lister->Discover(false);
-  linked_ptr<ServiceTypeData> service_type_data(
-      new ServiceTypeData(std::move(dns_sd_device_lister)));
-  service_data_map_[service_type] = service_type_data;
+  service_data_map_[service_type] =
+      base::MakeUnique<ServiceTypeData>(std::move(dns_sd_device_lister));
   DispatchApiEvent(service_type);
 }
 
 void DnsSdRegistry::UnregisterDnsSdListener(const std::string& service_type) {
   VLOG(1) << "UnregisterDnsSdListener: " << service_type;
-  DnsSdRegistry::DnsSdServiceTypeDataMap::iterator it =
-      service_data_map_.find(service_type);
+  auto it = service_data_map_.find(service_type);
   if (it == service_data_map_.end())
     return;
 
   if (service_data_map_[service_type]->ListenerRemoved())
     service_data_map_.erase(it);
 }
 
 void DnsSdRegistry::ServiceChanged(const std::string& service_type,
                                    bool added,
                                    const DnsSdService& service) {
@@ skipping 51 matching lines @@
     observer.OnDnsSdEvent(service_type,
                           service_data_map_[service_type]->GetServiceList());
   }
 }
 
 bool DnsSdRegistry::IsRegistered(const std::string& service_type) {
   return service_data_map_.find(service_type) != service_data_map_.end();
 }
 
 }  // namespace extensions