HttpServerProperties - Don't persist if ClearAlternativeService is

net/http/http_server_properties_manager.cc

 // Copyright 2014 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 "net/http/http_server_properties_manager.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 226 matching lines @@
 void HttpServerPropertiesManager::ConfirmAlternativeService(
     const AlternativeService& alternative_service) {
   DCHECK(network_task_runner_->RunsTasksOnCurrentThread());
   http_server_properties_impl_->ConfirmAlternativeService(alternative_service);
   ScheduleUpdatePrefsOnNetworkThread(CONFIRM_ALTERNATIVE_SERVICE);
 }
 
 void HttpServerPropertiesManager::ClearAlternativeService(
     const HostPortPair& origin) {
   DCHECK(network_task_runner_->RunsTasksOnCurrentThread());
+  const AlternativeServiceMap& map =
+      http_server_properties_impl_->alternative_service_map();
+  size_t old_size = map.size();
   http_server_properties_impl_->ClearAlternativeService(origin);
-  ScheduleUpdatePrefsOnNetworkThread(CLEAR_ALTERNATIVE_SERVICE);
+  size_t new_size = map.size();
+  // Persist only if we have deleted an entry.
+  if (old_size != new_size)
+    ScheduleUpdatePrefsOnNetworkThread(CLEAR_ALTERNATIVE_SERVICE);
 }
 
 const AlternativeServiceMap&
 HttpServerPropertiesManager::alternative_service_map() const {
   DCHECK(network_task_runner_->RunsTasksOnCurrentThread());
   return http_server_properties_impl_->alternative_service_map();
 }
 
 base::Value* HttpServerPropertiesManager::GetAlternativeServiceInfoAsValue()
     const {
@@ skipping 697 matching lines @@
                                             server_network_stats_dict);
 }
 
 void HttpServerPropertiesManager::OnHttpServerPropertiesChanged() {
   DCHECK(pref_task_runner_->RunsTasksOnCurrentThread());
   if (!setting_prefs_)
     ScheduleUpdateCacheOnPrefThread();
 }
 
 }  // namespace net