Fix a bug in HttpServerPropertiesImpl::HasAlternateProtocol

where Alternate-Protcol probability was not respected for
canonical servers.

BUG=437911

Review URL: https://codereview.chromium.org/768213002

Cr-Commit-Position: refs/heads/master@{#306288}

2 files changed, 38 insertions, 4 deletions

diff --git a/net/http/http_server_properties_impl.cc b/net/http/http_server_properties_impl.cc
index 1bf541b..477a68f 100644
--- a/net/http/http_server_properties_impl.cc
+++ b/net/http/http_server_properties_impl.cc
@@ -204,12 +204,16 @@ bool HttpServerPropertiesImpl::HasAlternateProtocol(
   if (g_forced_alternate_protocol)
     return true;
   AlternateProtocolMap::const_iterator it = alternate_protocol_map_.Get(server);
-  if (it != alternate_protocol_map_.end() &&
-      it->second.probability >= alternate_protocol_probability_threshold_) {
-    return true;
+  if (it != alternate_protocol_map_.end())
+    return it->second.probability >= alternate_protocol_probability_threshold_;
+
+  auto canonical = GetCanonicalHost(server);
+  if (canonical == canonical_host_to_origin_map_.end() ||
+      canonical->second.Equals(server)) {
+    return false;
   }
 
-  return GetCanonicalHost(server) != canonical_host_to_origin_map_.end();
+  return HasAlternateProtocol(canonical->second);
 }
 
 std::string HttpServerPropertiesImpl::GetCanonicalSuffix(
diff --git a/net/http/http_server_properties_impl_unittest.cc b/net/http/http_server_properties_impl_unittest.cc
index 3d1bacb..572b0fb 100644
--- a/net/http/http_server_properties_impl_unittest.cc
+++ b/net/http/http_server_properties_impl_unittest.cc
@@ -445,6 +445,36 @@ TEST_F(AlternateProtocolServerPropertiesTest, Canonical) {
   EXPECT_EQ(".c.youtube.com", impl_.GetCanonicalSuffix(canonical_port_pair));
 }
 
+TEST_F(AlternateProtocolServerPropertiesTest, CanonicalBelowThreshold) {
+  impl_.SetAlternateProtocolProbabilityThreshold(0.02);
+
+  HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
+  HostPortPair canonical_port_pair("bar.c.youtube.com", 80);
+  AlternateProtocolInfo canonical_protocol(1234, QUIC, 0.01);
+
+  impl_.SetAlternateProtocol(canonical_port_pair,
+                             canonical_protocol.port,
+                             canonical_protocol.protocol,
+                             canonical_protocol.probability);
+  EXPECT_FALSE(impl_.HasAlternateProtocol(canonical_port_pair));
+  EXPECT_FALSE(impl_.HasAlternateProtocol(test_host_port_pair));
+}
+
+TEST_F(AlternateProtocolServerPropertiesTest, CanonicalAboveThreshold) {
+  impl_.SetAlternateProtocolProbabilityThreshold(0.02);
+
+  HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
+  HostPortPair canonical_port_pair("bar.c.youtube.com", 80);
+  AlternateProtocolInfo canonical_protocol(1234, QUIC, 0.03);
+
+  impl_.SetAlternateProtocol(canonical_port_pair,
+                             canonical_protocol.port,
+                             canonical_protocol.protocol,
+                             canonical_protocol.probability);
+  EXPECT_TRUE(impl_.HasAlternateProtocol(canonical_port_pair));
+  EXPECT_TRUE(impl_.HasAlternateProtocol(test_host_port_pair));
+}
+
 TEST_F(AlternateProtocolServerPropertiesTest, ClearCanonical) {
   HostPortPair test_host_port_pair("foo.c.youtube.com", 80);
   HostPortPair canonical_port_pair("bar.c.youtube.com", 80);