HttpServerProperties - Don't persist if ClearAlternativeService is

net/http/http_server_properties_manager.cc

Index: net/http/http_server_properties_manager.cc
diff --git a/net/http/http_server_properties_manager.cc b/net/http/http_server_properties_manager.cc
index c4d1a1ac7613638c03de1f233446fc08c1ce84c2..cab6a156cfb1d35457396e2b11a1382109cda0fe 100644
--- a/net/http/http_server_properties_manager.cc
+++ b/net/http/http_server_properties_manager.cc
@@ -244,8 +244,14 @@ void HttpServerPropertiesManager::ConfirmAlternativeService(
 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&