Do not persist HttpServerProperties to disk that often.

net/http/http_server_properties.h

 // 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.
 
 #ifndef NET_HTTP_HTTP_SERVER_PROPERTIES_H_
 #define NET_HTTP_HTTP_SERVER_PROPERTIES_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 247 matching lines @@
                                 SSLConfig* ssl_config) = 0;
 
   // Return all alternative services for |origin|, including broken ones.
   // Returned alternative services never have empty hostnames.
   virtual AlternativeServiceVector GetAlternativeServices(
       const url::SchemeHostPort& origin) = 0;
 
   // Set a single alternative service for |origin|.  Previous alternative
   // services for |origin| are discarded.
   // |alternative_service.host| may be empty.
-  // Return true if |alternative_service_map_| is changed.
+  // Return true if |alternative_service_map_| has changed significantly enough
+  // that it should be persisted to disk.
   virtual bool SetAlternativeService(
       const url::SchemeHostPort& origin,
       const AlternativeService& alternative_service,
       base::Time expiration) = 0;
 
   // Set alternative services for |origin|.  Previous alternative services for
   // |origin| are discarded.
   // Hostnames in |alternative_service_info_vector| may be empty.
-  // Return true if |alternative_service_map_| is changed.
+  // |alternative_service_info_vector| may be empty.
+  // Return true if |alternative_service_map_| has changed significantly enough
+  // that it should be persisted to disk.
   virtual bool SetAlternativeServices(
       const url::SchemeHostPort& origin,
       const AlternativeServiceInfoVector& alternative_service_info_vector) = 0;
 
   // Marks |alternative_service| as broken.
   // |alternative_service.host| must not be empty.
   virtual void MarkAlternativeServiceBroken(
       const AlternativeService& alternative_service) = 0;
 
   // Marks |alternative_service| as recently broken.
@@ skipping 79 matching lines @@
   virtual void SetMaxServerConfigsStoredInProperties(
       size_t max_server_configs_stored_in_properties) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HttpServerProperties);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_SERVER_PROPERTIES_H_