Do not persist HttpServerProperties to disk that often.

net/http/http_server_properties_manager_unittest.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 <memory>
 #include <utility>
 
 #include "base/json/json_reader.h"
@@ skipping 695 matching lines @@
   // Verify that there are no entries in the settings map.
   const SpdySettingsMap& spdy_settings_map2_ret =
       http_server_props_manager_->spdy_settings_map();
   ASSERT_EQ(0U, spdy_settings_map2_ret.size());
 
   Mock::VerifyAndClearExpectations(http_server_props_manager_.get());
 }
 
 TEST_P(HttpServerPropertiesManagerTest, GetAlternativeServices) {
   ExpectPrefsUpdate();
+  // ScheduleUpdatePrefsOnNetworkThread() should be called only once.
   ExpectScheduleUpdatePrefsOnNetworkThread();
 
   url::SchemeHostPort spdy_server_mail("http", "mail.google.com", 80);
   EXPECT_FALSE(HasAlternativeService(spdy_server_mail));
   const AlternativeService alternative_service(NPN_HTTP_2, "mail.google.com",
                                                443);
+
   http_server_props_manager_->SetAlternativeService(
       spdy_server_mail, alternative_service, one_day_from_now_);
-  // ExpectScheduleUpdatePrefsOnNetworkThread() should be called only once.
+  base::RunLoop().RunUntilIdle();
+
   http_server_props_manager_->SetAlternativeService(
       spdy_server_mail, alternative_service, one_day_from_now_);
+  base::RunLoop().RunUntilIdle();
 
-  // Run the task.
-  base::RunLoop().RunUntilIdle();
   Mock::VerifyAndClearExpectations(http_server_props_manager_.get());
 
   AlternativeServiceVector alternative_service_vector =
       http_server_props_manager_->GetAlternativeServices(spdy_server_mail);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service, alternative_service_vector[0]);
 }
 
 TEST_P(HttpServerPropertiesManagerTest, SetAlternativeServices) {
   ExpectPrefsUpdate();
+  // ScheduleUpdatePrefsOnNetworkThread() should be called only once.
   ExpectScheduleUpdatePrefsOnNetworkThread();
 
   url::SchemeHostPort spdy_server_mail("http", "mail.google.com", 80);
   EXPECT_FALSE(HasAlternativeService(spdy_server_mail));
   AlternativeServiceInfoVector alternative_service_info_vector;
   const AlternativeService alternative_service1(NPN_HTTP_2, "mail.google.com",
                                                 443);
   alternative_service_info_vector.push_back(
       AlternativeServiceInfo(alternative_service1, one_day_from_now_));
   const AlternativeService alternative_service2(QUIC, "mail.google.com", 1234);
   alternative_service_info_vector.push_back(
       AlternativeServiceInfo(alternative_service2, one_day_from_now_));
+
   http_server_props_manager_->SetAlternativeServices(
       spdy_server_mail, alternative_service_info_vector);
-  // ExpectScheduleUpdatePrefsOnNetworkThread() should be called only once.
+  base::RunLoop().RunUntilIdle();
+
   http_server_props_manager_->SetAlternativeServices(
       spdy_server_mail, alternative_service_info_vector);
+  base::RunLoop().RunUntilIdle();
 
-  // Run the task.
-  base::RunLoop().RunUntilIdle();
   Mock::VerifyAndClearExpectations(http_server_props_manager_.get());
 
   AlternativeServiceVector alternative_service_vector =
       http_server_props_manager_->GetAlternativeServices(spdy_server_mail);
   ASSERT_EQ(2u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
   EXPECT_EQ(alternative_service2, alternative_service_vector[1]);
 }
 
-TEST_P(HttpServerPropertiesManagerTest, SetAlternativeServicesEmpty) {

[Bence, 2016/07/22 16:28:54]

I'm removing this test because now even empty => empty updates are persisted if
more than five minutes have passed since the last update or if it's the first
one.

I could change SetAlternativeServices return type to an enum to address this,
but this should be quite rare, I'm not sure it's worth the complexity.

-  url::SchemeHostPort spdy_server_mail("http", "mail.google.com", 80);
-  EXPECT_FALSE(HasAlternativeService(spdy_server_mail));
-  const AlternativeService alternative_service(NPN_HTTP_2, "mail.google.com",
-                                               443);
-  http_server_props_manager_->SetAlternativeServices(
-      spdy_server_mail, AlternativeServiceInfoVector());
-  // ExpectScheduleUpdatePrefsOnNetworkThread() should not be called.
-
-  // Run the task.
-  base::RunLoop().RunUntilIdle();
-  Mock::VerifyAndClearExpectations(http_server_props_manager_.get());
-
-  EXPECT_FALSE(HasAlternativeService(spdy_server_mail));
-}
-
 TEST_P(HttpServerPropertiesManagerTest, ConfirmAlternativeService) {
   ExpectPrefsUpdate();
 
   url::SchemeHostPort spdy_server_mail("http", "mail.google.com", 80);
   EXPECT_FALSE(HasAlternativeService(spdy_server_mail));
   AlternativeService alternative_service(NPN_HTTP_2, "mail.google.com", 443);
 
   ExpectScheduleUpdatePrefsOnNetworkThread();
   http_server_props_manager_->SetAlternativeService(
       spdy_server_mail, alternative_service, one_day_from_now_);
@@ skipping 588 matching lines @@
   // Shutdown comes before the task is executed.
   http_server_props_manager_->ShutdownOnPrefThread();
   // Run the task after shutdown, but before deletion.
   base::RunLoop().RunUntilIdle();
   Mock::VerifyAndClearExpectations(http_server_props_manager_.get());
   http_server_props_manager_.reset();
   base::RunLoop().RunUntilIdle();
 }
 
 }  // namespace net