Revert of Remove support for Alt-Svc/Alternate Protocol Probability

net/http/http_server_properties_impl_unittest.cc

 // 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.
 
 #include "net/http/http_server_properties_impl.h"
 
 #include <string>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
@@ skipping 44 matching lines @@
 
 class HttpServerPropertiesImplTest : public testing::Test {
  protected:
   bool HasAlternativeService(const HostPortPair& origin) {
     const AlternativeServiceVector alternative_service_vector =
         impl_.GetAlternativeServices(origin);
     return !alternative_service_vector.empty();
   }
 
   bool SetAlternativeService(const HostPortPair& origin,
-                             const AlternativeService& alternative_service) {
+                             const AlternativeService& alternative_service,
+                             double alternative_probability) {
     const base::Time expiration =
         base::Time::Now() + base::TimeDelta::FromDays(1);
-    return impl_.SetAlternativeService(origin, alternative_service, expiration);
+    return impl_.SetAlternativeService(origin, alternative_service,
+                                       alternative_probability, expiration);
   }
 
   void InitializeSpdySettingsUploadBandwidth(SpdySettingsMap* spdy_settings_map,
                                              const HostPortPair& spdy_server,
                                              uint32_t value) {
     SettingsMap settings_map;
     settings_map[kSpdySettingsId] =
         SettingsFlagsAndValue(kSpdySettingsFlags, value);
     spdy_settings_map->Put(spdy_server, settings_map);
   }
@@ skipping 135 matching lines @@
   EXPECT_FALSE(impl_.SupportsRequestPriority(spdy_server_mail));
 
   // Add docs.google.com:443 as supporting SPDY.
   HostPortPair spdy_server_docs("docs.google.com", 443);
   impl_.SetSupportsSpdy(spdy_server_docs, true);
   EXPECT_TRUE(impl_.SupportsRequestPriority(spdy_server_docs));
 
   // Add www.youtube.com:443 as supporting QUIC.
   HostPortPair quic_server_youtube("www.youtube.com", 443);
   const AlternativeService alternative_service1(QUIC, "www.youtube.com", 443);
-  SetAlternativeService(quic_server_youtube, alternative_service1);
+  SetAlternativeService(quic_server_youtube, alternative_service1, 1.0);
   EXPECT_TRUE(impl_.SupportsRequestPriority(quic_server_youtube));
 
   // Add www.example.com:443 with two alternative services, one supporting QUIC.
   HostPortPair quic_server_example("www.example.com", 443);
   const AlternativeService alternative_service2(NPN_HTTP_2, "", 443);
-  SetAlternativeService(quic_server_example, alternative_service2);
-  SetAlternativeService(quic_server_example, alternative_service1);
+  SetAlternativeService(quic_server_example, alternative_service2, 1.0);
+  SetAlternativeService(quic_server_example, alternative_service1, 1.0);
   EXPECT_TRUE(impl_.SupportsRequestPriority(quic_server_example));
 
   // Verify all the entries are the same after additions.
   EXPECT_TRUE(impl_.SupportsRequestPriority(spdy_server_google));
   EXPECT_FALSE(impl_.SupportsRequestPriority(spdy_server_mail));
   EXPECT_TRUE(impl_.SupportsRequestPriority(spdy_server_docs));
   EXPECT_TRUE(impl_.SupportsRequestPriority(quic_server_youtube));
   EXPECT_TRUE(impl_.SupportsRequestPriority(quic_server_example));
 }
 
@@ skipping 107 matching lines @@
   ASSERT_EQ(spdy_server_m, string_value_m);
 }
 
 typedef HttpServerPropertiesImplTest AlternateProtocolServerPropertiesTest;
 
 TEST_F(AlternateProtocolServerPropertiesTest, Basic) {
   HostPortPair test_host_port_pair("foo", 80);
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 
   AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
-  SetAlternativeService(test_host_port_pair, alternative_service);
+  SetAlternativeService(test_host_port_pair, alternative_service, 1.0);
   const AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service, alternative_service_vector[0]);
 
   impl_.Clear();
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, ExcludeOrigin) {
   AlternativeServiceInfoVector alternative_service_info_vector;
   base::Time expiration = base::Time::Now() + base::TimeDelta::FromDays(1);
   // Same hostname, same port, TCP: should be ignored.
   AlternativeService alternative_service1(NPN_HTTP_2, "foo", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service1, expiration));
+      AlternativeServiceInfo(alternative_service1, 1.0, expiration));
   // Different hostname: GetAlternativeServices should return this one.
   AlternativeService alternative_service2(NPN_HTTP_2, "bar", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, expiration));
+      AlternativeServiceInfo(alternative_service2, 1.0, expiration));
   // Different port: GetAlternativeServices should return this one too.
   AlternativeService alternative_service3(NPN_HTTP_2, "foo", 80);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service3, expiration));
+      AlternativeServiceInfo(alternative_service3, 1.0, expiration));
   // QUIC: GetAlternativeServices should return this one too.
   AlternativeService alternative_service4(QUIC, "foo", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service4, expiration));
+      AlternativeServiceInfo(alternative_service4, 1.0, expiration));
 
   HostPortPair test_host_port_pair("foo", 443);
   impl_.SetAlternativeServices(test_host_port_pair,
                                alternative_service_info_vector);
 
   const AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(3u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service2, alternative_service_vector[0]);
   EXPECT_EQ(alternative_service3, alternative_service_vector[1]);
   EXPECT_EQ(alternative_service4, alternative_service_vector[2]);
 }
 
+TEST_F(AlternateProtocolServerPropertiesTest, DefaultProbabilityExcluded) {
+  HostPortPair test_host_port_pair("foo", 80);
+  const AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
+  SetAlternativeService(test_host_port_pair, alternative_service, 0.99);
+
+  EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
+}
+
+// GetAlternativeServices and HasAlternativeServices should only return the ones
+// with probability greater than or equal to the threshold.
+TEST_F(AlternateProtocolServerPropertiesTest, Probability) {
+  impl_.SetAlternativeServiceProbabilityThreshold(0.5);
+
+  AlternativeServiceInfoVector alternative_service_info_vector;
+  base::Time expiration = base::Time::Now() + base::TimeDelta::FromDays(1);
+  const AlternativeService alternative_service1(NPN_HTTP_2, "foo", 443);
+  alternative_service_info_vector.push_back(
+      AlternativeServiceInfo(alternative_service1, 0.3, expiration));
+  const AlternativeService alternative_service2(QUIC, "bar", 123);
+  alternative_service_info_vector.push_back(
+      AlternativeServiceInfo(alternative_service2, 0.7, expiration));
+  const AlternativeService alternative_service3(NPN_SPDY_3_1, "baz", 443);
+  alternative_service_info_vector.push_back(
+      AlternativeServiceInfo(alternative_service3, 0.4, expiration));
+  const AlternativeService alternative_service4(NPN_HTTP_2, "qux", 1234);
+  alternative_service_info_vector.push_back(
+      AlternativeServiceInfo(alternative_service4, 0.6, expiration));
+
+  HostPortPair test_host_port_pair("foo", 80);
+  impl_.SetAlternativeServices(test_host_port_pair,
+                               alternative_service_info_vector);
+
+  const AlternativeServiceVector alternative_service_vector =
+      impl_.GetAlternativeServices(test_host_port_pair);
+  ASSERT_EQ(2u, alternative_service_vector.size());
+  EXPECT_EQ(alternative_service2, alternative_service_vector[0]);
+  EXPECT_EQ(alternative_service4, alternative_service_vector[1]);
+}
+
+TEST_F(AlternateProtocolServerPropertiesTest, ProbabilityExcluded) {
+  impl_.SetAlternativeServiceProbabilityThreshold(0.75);
+
+  HostPortPair test_host_port_pair("foo", 80);
+  const AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
+  SetAlternativeService(test_host_port_pair, alternative_service, 0.5);
+  EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
+}
+
+TEST_F(AlternateProtocolServerPropertiesTest, ZeroProbabilityAlwaysExcluded) {
+  impl_.SetAlternativeServiceProbabilityThreshold(0.0);
+
+  HostPortPair test_host_port_pair("foo", 80);
+  const AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
+  SetAlternativeService(test_host_port_pair, alternative_service, 0);
+  EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
+}
+
 TEST_F(AlternateProtocolServerPropertiesTest, Initialize) {
   // |test_host_port_pair1| has an alternative service, which will not be
   // affected by InitializeAlternativeServiceServers(), because
   // |alternative_service_map| does not have an entry for
   // |test_host_port_pair1|.
   HostPortPair test_host_port_pair1("foo1", 80);
   const AlternativeService alternative_service1(NPN_HTTP_2, "bar1", 443);
   const base::Time now = base::Time::Now();
   base::Time expiration1 = now + base::TimeDelta::FromDays(1);
   // 1st entry in the memory.
-  impl_.SetAlternativeService(test_host_port_pair1, alternative_service1,
+  impl_.SetAlternativeService(test_host_port_pair1, alternative_service1, 1.0,
                               expiration1);
 
   // |test_host_port_pair2| has an alternative service, which will be
   // overwritten by InitializeAlternativeServiceServers(), because
   // |alternative_service_map| has an entry for
   // |test_host_port_pair2|.
   AlternativeServiceInfoVector alternative_service_info_vector;
   const AlternativeService alternative_service2(NPN_SPDY_3_1, "bar2", 443);
   base::Time expiration2 = now + base::TimeDelta::FromDays(2);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, expiration2));
+      AlternativeServiceInfo(alternative_service2, 1.0, expiration2));
   HostPortPair test_host_port_pair2("foo2", 80);
   // 0th entry in the memory.
   impl_.SetAlternativeServices(test_host_port_pair2,
                                alternative_service_info_vector);
 
   // Prepare |alternative_service_map| to be loaded by
   // InitializeAlternativeServiceServers().
   AlternativeServiceMap alternative_service_map(
       AlternativeServiceMap::NO_AUTO_EVICT);
   const AlternativeService alternative_service3(NPN_HTTP_2, "bar3", 123);
   base::Time expiration3 = now + base::TimeDelta::FromDays(3);
   const AlternativeServiceInfo alternative_service_info1(alternative_service3,
-                                                         expiration3);
+                                                         0.7, expiration3);
   // Simulate updating data for 0th entry with data from Preferences.
   alternative_service_map.Put(
       test_host_port_pair2,
       AlternativeServiceInfoVector(/*size=*/1, alternative_service_info1));
 
   HostPortPair test_host_port_pair3("foo3", 80);
   const AlternativeService alternative_service4(NPN_HTTP_2, "bar4", 1234);
   base::Time expiration4 = now + base::TimeDelta::FromDays(4);
   const AlternativeServiceInfo alternative_service_info2(alternative_service4,
-                                                         expiration4);
+                                                         0.2, expiration4);
   // Add an old entry from Preferences, this will be added to end of recency
   // list.
   alternative_service_map.Put(
       test_host_port_pair3,
       AlternativeServiceInfoVector(/*size=*/1, alternative_service_info2));
 
   // MRU list will be test_host_port_pair2, test_host_port_pair1,
   // test_host_port_pair3.
   impl_.InitializeAlternativeServiceServers(&alternative_service_map);
 
   // Verify alternative_service_map.
   const AlternativeServiceMap& map = impl_.alternative_service_map();
   ASSERT_EQ(3u, map.size());
   AlternativeServiceMap::const_iterator map_it = map.begin();
 
   EXPECT_TRUE(map_it->first.Equals(test_host_port_pair2));
   ASSERT_EQ(1u, map_it->second.size());
   EXPECT_EQ(alternative_service3, map_it->second[0].alternative_service);
+  EXPECT_EQ(0.7, map_it->second[0].probability);
   EXPECT_EQ(expiration3, map_it->second[0].expiration);
   ++map_it;
   EXPECT_TRUE(map_it->first.Equals(test_host_port_pair1));
   ASSERT_EQ(1u, map_it->second.size());
   EXPECT_EQ(alternative_service1, map_it->second[0].alternative_service);
+  EXPECT_EQ(1.0, map_it->second[0].probability);
   EXPECT_EQ(expiration1, map_it->second[0].expiration);
   ++map_it;
   EXPECT_TRUE(map_it->first.Equals(test_host_port_pair3));
   ASSERT_EQ(1u, map_it->second.size());
   EXPECT_EQ(alternative_service4, map_it->second[0].alternative_service);
+  EXPECT_EQ(0.2, map_it->second[0].probability);
   EXPECT_EQ(expiration4, map_it->second[0].expiration);
 }
 
 // Regression test for https://crbug.com/504032:
 // InitializeAlternativeServiceServers() should not crash if there is an empty
 // hostname is the mapping.
 TEST_F(AlternateProtocolServerPropertiesTest, InitializeWithEmptyHostname) {
   const HostPortPair host_port_pair("foo", 443);
   const AlternativeService alternative_service_with_empty_hostname(NPN_HTTP_2,
                                                                    "", 1234);
   const AlternativeService alternative_service_with_foo_hostname(NPN_HTTP_2,
                                                                  "foo", 1234);
-  SetAlternativeService(host_port_pair,
-                        alternative_service_with_empty_hostname);
+  SetAlternativeService(host_port_pair, alternative_service_with_empty_hostname,
+                        1.0);
   impl_.MarkAlternativeServiceBroken(alternative_service_with_foo_hostname);
 
   AlternativeServiceMap alternative_service_map(
       AlternativeServiceMap::NO_AUTO_EVICT);
   impl_.InitializeAlternativeServiceServers(&alternative_service_map);
 
   EXPECT_TRUE(
       impl_.IsAlternativeServiceBroken(alternative_service_with_foo_hostname));
   const AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service_with_foo_hostname,
             alternative_service_vector[0]);
 }
 
 // Regression test for https://crbug.com/516486:
 // GetAlternativeServices() should remove |alternative_service_map_| elements
 // with empty value.
 TEST_F(AlternateProtocolServerPropertiesTest, EmptyVector) {
   HostPortPair host_port_pair("foo", 443);
   const AlternativeService alternative_service(NPN_HTTP_2, "bar", 443);
   base::Time expiration = base::Time::Now() - base::TimeDelta::FromDays(1);
   const AlternativeServiceInfo alternative_service_info(alternative_service,
-                                                        expiration);
+                                                        1.0, expiration);
   AlternativeServiceMap alternative_service_map(
       AlternativeServiceMap::NO_AUTO_EVICT);
   alternative_service_map.Put(
       host_port_pair,
       AlternativeServiceInfoVector(/*size=*/1, alternative_service_info));
 
   // Prepare |alternative_service_map_| with a single key that has a single
   // AlternativeServiceInfo with identical hostname and port.
   impl_.InitializeAlternativeServiceServers(&alternative_service_map);
 
@@ skipping 15 matching lines @@
   ASSERT_TRUE(alternative_service_vector.empty());
 }
 
 // Regression test for https://crbug.com/516486 for the canonical host case.
 TEST_F(AlternateProtocolServerPropertiesTest, EmptyVectorForCanonical) {
   HostPortPair host_port_pair("foo.c.youtube.com", 443);
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 443);
   const AlternativeService alternative_service(NPN_HTTP_2, "", 443);
   base::Time expiration = base::Time::Now() - base::TimeDelta::FromDays(1);
   const AlternativeServiceInfo alternative_service_info(alternative_service,
-                                                        expiration);
+                                                        1.0, expiration);
   AlternativeServiceMap alternative_service_map(
       AlternativeServiceMap::NO_AUTO_EVICT);
   alternative_service_map.Put(
       canonical_host_port_pair,
       AlternativeServiceInfoVector(/*size=*/1, alternative_service_info));
 
   // Prepare |alternative_service_map_| with a single key that has a single
   // AlternativeServiceInfo with identical hostname and port.
   impl_.InitializeAlternativeServiceServers(&alternative_service_map);
 
@@ skipping 14 matching lines @@
   // There should still be no alternative service assigned to
   // |canonical_host_port_pair|.
   alternative_service_vector =
       impl_.GetAlternativeServices(canonical_host_port_pair);
   ASSERT_TRUE(alternative_service_vector.empty());
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, MRUOfGetAlternativeServices) {
   HostPortPair test_host_port_pair1("foo1", 80);
   const AlternativeService alternative_service1(NPN_SPDY_3_1, "foo1", 443);
-  SetAlternativeService(test_host_port_pair1, alternative_service1);
+  SetAlternativeService(test_host_port_pair1, alternative_service1, 1.0);
   HostPortPair test_host_port_pair2("foo2", 80);
   const AlternativeService alternative_service2(NPN_HTTP_2, "foo2", 1234);
-  SetAlternativeService(test_host_port_pair2, alternative_service2);
+  SetAlternativeService(test_host_port_pair2, alternative_service2, 1.0);
 
   const AlternativeServiceMap& map = impl_.alternative_service_map();
   AlternativeServiceMap::const_iterator it = map.begin();
   EXPECT_TRUE(it->first.Equals(test_host_port_pair2));
   ASSERT_EQ(1u, it->second.size());
   EXPECT_EQ(alternative_service2, it->second[0].alternative_service);
 
   const AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair1);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
 
   // GetAlternativeServices should reorder the AlternateProtocol map.
   it = map.begin();
   EXPECT_TRUE(it->first.Equals(test_host_port_pair1));
   ASSERT_EQ(1u, it->second.size());
   EXPECT_EQ(alternative_service1, it->second[0].alternative_service);
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, SetBroken) {
   HostPortPair test_host_port_pair("foo", 80);
   const AlternativeService alternative_service1(NPN_HTTP_2, "foo", 443);
-  SetAlternativeService(test_host_port_pair, alternative_service1);
+  SetAlternativeService(test_host_port_pair, alternative_service1, 1.0);
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service1));
 
   // GetAlternativeServices should return the broken alternative service.
   impl_.MarkAlternativeServiceBroken(alternative_service1);
   alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service1));
 
   // SetAlternativeServices should add a broken alternative service to the map.
   AlternativeServiceInfoVector alternative_service_info_vector;
   base::Time expiration = base::Time::Now() + base::TimeDelta::FromDays(1);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service1, expiration));
+      AlternativeServiceInfo(alternative_service1, 1.0, expiration));
   const AlternativeService alternative_service2(NPN_HTTP_2, "foo", 1234);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, expiration));
+      AlternativeServiceInfo(alternative_service2, 1.0, expiration));
   impl_.SetAlternativeServices(test_host_port_pair,
                                alternative_service_info_vector);
   alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(2u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
   EXPECT_EQ(alternative_service2, alternative_service_vector[1]);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service_vector[0]));
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service_vector[1]));
 
   // SetAlternativeService should add a broken alternative service to the map.
-  SetAlternativeService(test_host_port_pair, alternative_service1);
+  SetAlternativeService(test_host_port_pair, alternative_service1, 1.0);
   alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service1, alternative_service_vector[0]);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service_vector[0]));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, MaxAge) {
   AlternativeServiceInfoVector alternative_service_info_vector;
   base::Time now = base::Time::Now();
   base::TimeDelta one_day = base::TimeDelta::FromDays(1);
 
   // First alternative service expired one day ago, should not be returned by
   // GetAlternativeServices().
   const AlternativeService alternative_service1(NPN_SPDY_3_1, "foo", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service1, now - one_day));
+      AlternativeServiceInfo(alternative_service1, 1.0, now - one_day));
 
   // Second alterrnative service will expire one day from now, should be
   // returned by GetAlternativeSerices().
   const AlternativeService alternative_service2(NPN_HTTP_2, "bar", 1234);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, now + one_day));
+      AlternativeServiceInfo(alternative_service2, 1.0, now + one_day));
 
   HostPortPair test_host_port_pair("foo", 80);
   impl_.SetAlternativeServices(test_host_port_pair,
                                alternative_service_info_vector);
 
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service2, alternative_service_vector[0]);
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, MaxAgeCanonical) {
   AlternativeServiceInfoVector alternative_service_info_vector;
   base::Time now = base::Time::Now();
   base::TimeDelta one_day = base::TimeDelta::FromDays(1);
 
   // First alternative service expired one day ago, should not be returned by
   // GetAlternativeServices().
   const AlternativeService alternative_service1(NPN_SPDY_3_1, "foo", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service1, now - one_day));
+      AlternativeServiceInfo(alternative_service1, 1.0, now - one_day));
 
   // Second alterrnative service will expire one day from now, should be
   // returned by GetAlternativeSerices().
   const AlternativeService alternative_service2(NPN_HTTP_2, "bar", 1234);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, now + one_day));
+      AlternativeServiceInfo(alternative_service2, 1.0, now + one_day));
 
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   impl_.SetAlternativeServices(canonical_host_port_pair,
                                alternative_service_info_vector);
 
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(alternative_service2, alternative_service_vector[0]);
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, ClearAlternativeServices) {
   AlternativeServiceInfoVector alternative_service_info_vector;
   const AlternativeService alternative_service1(NPN_SPDY_3_1, "foo", 443);
   base::Time expiration = base::Time::Now() + base::TimeDelta::FromDays(1);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service1, expiration));
+      AlternativeServiceInfo(alternative_service1, 1.0, expiration));
   const AlternativeService alternative_service2(NPN_HTTP_2, "bar", 1234);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(alternative_service2, expiration));
+      AlternativeServiceInfo(alternative_service2, 1.0, expiration));
   HostPortPair test_host_port_pair("foo", 80);
   impl_.SetAlternativeServices(test_host_port_pair,
                                alternative_service_info_vector);
 
   const net::AlternativeServiceMap& map = impl_.alternative_service_map();
   net::AlternativeServiceMap::const_iterator it = map.begin();
   EXPECT_TRUE(it->first.Equals(test_host_port_pair));
   ASSERT_EQ(2u, it->second.size());
   EXPECT_EQ(alternative_service1, it->second[0].alternative_service);
   EXPECT_EQ(alternative_service2, it->second[1].alternative_service);
 
   impl_.ClearAlternativeServices(test_host_port_pair);
   EXPECT_TRUE(map.empty());
 }
 
 // A broken alternative service in the mapping carries meaningful information,
 // therefore it should not be ignored by SetAlternativeService().  In
 // particular, an alternative service mapped to an origin shadows alternative
 // services of canonical hosts.
 TEST_F(AlternateProtocolServerPropertiesTest, BrokenShadowsCanonical) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
                                                    1234);
-  SetAlternativeService(canonical_host_port_pair,
-                        canonical_alternative_service);
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        1.0);
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(canonical_alternative_service, alternative_service_vector[0]);
 
   const AlternativeService broken_alternative_service(NPN_HTTP_2, "foo", 443);
   impl_.MarkAlternativeServiceBroken(broken_alternative_service);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(broken_alternative_service));
 
-  SetAlternativeService(test_host_port_pair, broken_alternative_service);
+  SetAlternativeService(test_host_port_pair, broken_alternative_service, 1.0);
   alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(broken_alternative_service, alternative_service_vector[0]);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(broken_alternative_service));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, ClearBroken) {
   HostPortPair test_host_port_pair("foo", 80);
   const AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
-  SetAlternativeService(test_host_port_pair, alternative_service);
+  SetAlternativeService(test_host_port_pair, alternative_service, 1.0);
   impl_.MarkAlternativeServiceBroken(alternative_service);
   ASSERT_TRUE(HasAlternativeService(test_host_port_pair));
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service));
   // ClearAlternativeServices should leave a broken alternative service marked
   // as such.
   impl_.ClearAlternativeServices(test_host_port_pair);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, MarkRecentlyBroken) {
   HostPortPair host_port_pair("foo", 80);
   const AlternativeService alternative_service(NPN_HTTP_2, "foo", 443);
-  SetAlternativeService(host_port_pair, alternative_service);
+  SetAlternativeService(host_port_pair, alternative_service, 1.0);
 
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_FALSE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 
   impl_.MarkAlternativeServiceRecentlyBroken(alternative_service);
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_TRUE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 
   impl_.ConfirmAlternativeService(alternative_service);
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_FALSE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, Canonical) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   EXPECT_FALSE(HasAlternativeService(canonical_host_port_pair));
 
   AlternativeServiceInfoVector alternative_service_info_vector;
   const AlternativeService canonical_alternative_service1(
       QUIC, "bar.c.youtube.com", 1234);
   base::Time expiration = base::Time::Now() + base::TimeDelta::FromDays(1);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(canonical_alternative_service1, expiration));
+      AlternativeServiceInfo(canonical_alternative_service1, 1.0, expiration));
   const AlternativeService canonical_alternative_service2(NPN_HTTP_2, "", 443);
   alternative_service_info_vector.push_back(
-      AlternativeServiceInfo(canonical_alternative_service2, expiration));
+      AlternativeServiceInfo(canonical_alternative_service2, 1.0, expiration));
   impl_.SetAlternativeServices(canonical_host_port_pair,
                                alternative_service_info_vector);
 
   // Since |test_host_port_pair| does not have an alternative service itself,
   // GetAlternativeServices should return those of |canonical_host_port_pair|.
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(2u, alternative_service_vector.size());
   EXPECT_EQ(canonical_alternative_service1, alternative_service_vector[0]);
 
   // Since |canonical_alternative_service2| has an empty host,
   // GetAlternativeServices should substitute the hostname of its |origin|
   // argument.
   EXPECT_EQ(test_host_port_pair.host(), alternative_service_vector[1].host);
   EXPECT_EQ(canonical_alternative_service2.protocol,
             alternative_service_vector[1].protocol);
   EXPECT_EQ(canonical_alternative_service2.port,
             alternative_service_vector[1].port);
 
   // Verify the canonical suffix.
   EXPECT_EQ(".c.youtube.com",
             impl_.GetCanonicalSuffix(test_host_port_pair.host()));
   EXPECT_EQ(".c.youtube.com",
             impl_.GetCanonicalSuffix(canonical_host_port_pair.host()));
 }
 
+TEST_F(AlternateProtocolServerPropertiesTest, CanonicalBelowThreshold) {
+  impl_.SetAlternativeServiceProbabilityThreshold(0.02);
+
+  HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
+  HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
+  AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
+                                                   1234);
+
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        0.01);
+  EXPECT_FALSE(HasAlternativeService(canonical_host_port_pair));
+  EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
+}
+
+TEST_F(AlternateProtocolServerPropertiesTest, CanonicalAboveThreshold) {
+  impl_.SetAlternativeServiceProbabilityThreshold(0.02);
+
+  HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
+  HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
+  AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
+                                                   1234);
+
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        0.03);
+  EXPECT_TRUE(HasAlternativeService(canonical_host_port_pair));
+  EXPECT_TRUE(HasAlternativeService(test_host_port_pair));
+}
+
 TEST_F(AlternateProtocolServerPropertiesTest, ClearCanonical) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
                                                    1234);
 
-  SetAlternativeService(canonical_host_port_pair,
-                        canonical_alternative_service);
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        1.0);
   impl_.ClearAlternativeServices(canonical_host_port_pair);
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, CanonicalBroken) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
                                                    1234);
 
-  SetAlternativeService(canonical_host_port_pair,
-                        canonical_alternative_service);
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        1.0);
   impl_.MarkAlternativeServiceBroken(canonical_alternative_service);
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 }
 
 // Adding an alternative service for a new host overrides canonical host.
 TEST_F(AlternateProtocolServerPropertiesTest, CanonicalOverride) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair bar_host_port_pair("bar.c.youtube.com", 80);
   AlternativeService bar_alternative_service(QUIC, "bar.c.youtube.com", 1234);
-  SetAlternativeService(bar_host_port_pair, bar_alternative_service);
+  SetAlternativeService(bar_host_port_pair, bar_alternative_service, 1.0);
   AlternativeServiceVector alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(bar_alternative_service, alternative_service_vector[0]);
 
   HostPortPair qux_host_port_pair("qux.c.youtube.com", 80);
   AlternativeService qux_alternative_service(QUIC, "qux.c.youtube.com", 443);
-  SetAlternativeService(qux_host_port_pair, qux_alternative_service);
+  SetAlternativeService(qux_host_port_pair, qux_alternative_service, 1.0);
   alternative_service_vector =
       impl_.GetAlternativeServices(test_host_port_pair);
   ASSERT_EQ(1u, alternative_service_vector.size());
   EXPECT_EQ(qux_alternative_service, alternative_service_vector[0]);
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest, ClearWithCanonical) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair canonical_host_port_pair("bar.c.youtube.com", 80);
   AlternativeService canonical_alternative_service(QUIC, "bar.c.youtube.com",
                                                    1234);
 
-  SetAlternativeService(canonical_host_port_pair,
-                        canonical_alternative_service);
+  SetAlternativeService(canonical_host_port_pair, canonical_alternative_service,
+                        1.0);
   impl_.Clear();
   EXPECT_FALSE(HasAlternativeService(test_host_port_pair));
 }
 
 TEST_F(AlternateProtocolServerPropertiesTest,
        ExpireBrokenAlternateProtocolMappings) {
   HostPortPair host_port_pair("foo", 443);
   AlternativeService alternative_service(QUIC, "foo", 443);
-  SetAlternativeService(host_port_pair, alternative_service);
+  SetAlternativeService(host_port_pair, alternative_service, 1.0);
   EXPECT_TRUE(HasAlternativeService(host_port_pair));
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_FALSE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 
   base::TimeTicks past =
       base::TimeTicks::Now() - base::TimeDelta::FromSeconds(42);
   HttpServerPropertiesImplPeer::AddBrokenAlternativeServiceWithExpirationTime(
       impl_, alternative_service, past);
   EXPECT_TRUE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_TRUE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 
   HttpServerPropertiesImplPeer::ExpireBrokenAlternateProtocolMappings(impl_);
   EXPECT_FALSE(impl_.IsAlternativeServiceBroken(alternative_service));
   EXPECT_TRUE(impl_.WasAlternativeServiceRecentlyBroken(alternative_service));
 }
 
 // Regression test for https://crbug.com/505413.
 TEST_F(AlternateProtocolServerPropertiesTest, RemoveExpiredBrokenAltSvc) {
   HostPortPair foo_host_port_pair("foo", 443);
   AlternativeService bar_alternative_service(QUIC, "bar", 443);
-  SetAlternativeService(foo_host_port_pair, bar_alternative_service);
+  SetAlternativeService(foo_host_port_pair, bar_alternative_service, 1.0);
   EXPECT_TRUE(HasAlternativeService(foo_host_port_pair));
 
   HostPortPair bar_host_port_pair1("bar", 80);
   AlternativeService nohost_alternative_service(QUIC, "", 443);
-  SetAlternativeService(bar_host_port_pair1, nohost_alternative_service);
+  SetAlternativeService(bar_host_port_pair1, nohost_alternative_service, 1.0);
   EXPECT_TRUE(HasAlternativeService(bar_host_port_pair1));
 
   HostPortPair bar_host_port_pair2("bar", 443);
   AlternativeService baz_alternative_service(QUIC, "baz", 1234);
-  SetAlternativeService(bar_host_port_pair2, baz_alternative_service);
+  SetAlternativeService(bar_host_port_pair2, baz_alternative_service, 1.0);
   EXPECT_TRUE(HasAlternativeService(bar_host_port_pair2));
 
   // Mark "bar:443" as broken.
   base::TimeTicks past =
       base::TimeTicks::Now() - base::TimeDelta::FromSeconds(42);
   HttpServerPropertiesImplPeer::AddBrokenAlternativeServiceWithExpirationTime(
       impl_, bar_alternative_service, past);
 
   // Expire brokenness of "bar:443".
   HttpServerPropertiesImplPeer::ExpireBrokenAlternateProtocolMappings(impl_);
@@ skipping 462 matching lines @@
   EXPECT_EQ(quic_server_info1, *(impl_.GetQuicServerInfo(quic_server_id)));
 
   impl_.Clear();
   EXPECT_EQ(0u, impl_.quic_server_info_map().size());
   EXPECT_EQ(nullptr, impl_.GetQuicServerInfo(quic_server_id));
 }
 
 }  // namespace
 
 }  // namespace net