net/: Use both QUIC and TCP for initial URL requests

net/http/http_network_session.cc

@@ -393,6 +393,12 @@ void HttpNetworkSession::DisableQuic() {
   params_.enable_quic = false;
 }
 
+#if BUILDFLAG(IS_ANDROIDTV)
+bool HttpNetworkSession::UseQuicForUnknownOrigin() const {
+  return params_.use_quic_for_unknown_origins;
+}
+#endif
+
 bool HttpNetworkSession::ShouldForceQuic(const url::SchemeHostPort& destination,
                                          const ProxyInfo& proxy_info,
                                          bool is_websocket) {

net/http/http_network_session.h

@@ -149,6 +149,12 @@ struct NET_EXPORT HttpNetworkSessionParams {
   // Enables QUIC support.
   bool enable_quic = true;
 
+#if BUILDFLAG(IS_ANDROIDTV)
+  // If true, request to an origin without recorded alt-svc info will
+  // try to establish both QUIC and TCP connections and use the faster one.
+  bool use_quic_for_unknown_origins = false;
+#endif
+
   // If non-empty, QUIC will only be spoken to hosts in this list.
   base::flat_set<std::string> quic_host_allowlist;
 
@@ -303,6 +309,11 @@ class NET_EXPORT HttpNetworkSession : public base::PowerSuspendObserver {
   // Disable QUIC for new streams.
   void DisableQuic();
 
+#if BUILDFLAG(IS_ANDROIDTV)
+  // Whether to try QUIC connection for origins without alt-svc on record.
+  bool UseQuicForUnknownOrigin() const;
+#endif
+
   // Returns true when QUIC is forcibly used for `destination`.
   bool ShouldForceQuic(const url::SchemeHostPort& destination,
                        const ProxyInfo& proxy_info,

net/http/http_stream_factory_job_controller.cc

@@ -1272,6 +1272,22 @@ HttpStreamFactory::JobController::GetAlternativeServiceInfoInternal(
           url::SchemeHostPort(original_url),
           request_info.network_anonymization_key);
   if (alternative_service_info_vector.empty()) {
+#if BUILDFLAG(IS_ANDROIDTV)
+    if (session_->IsQuicEnabled() && session_->UseQuicForUnknownOrigin()) {
+      url::SchemeHostPort origin(original_url);
+#if defined(COBALT_BUILD_TYPE_GOLD)
+      const int kDefaultQUICServerPort = 443;
+      if (origin.port() == kDefaultQUICServerPort) {
+#endif
+        quic::ParsedQuicVersionVector versions = quic::AllSupportedVersions();
+        return AlternativeServiceInfo::CreateQuicAlternativeServiceInfo(
+            AlternativeService(NextProto::kProtoQUIC, origin.host(), origin.port()),
+            base::Time::Max(), versions);
+#if defined(COBALT_BUILD_TYPE_GOLD)
+      }
+#endif
+    }
+#endif  // BUILDFLAG(IS_ANDROIDTV)
     return AlternativeServiceInfo();
   }
 

services/network/network_context.cc

@@ -2914,6 +2914,10 @@ URLRequestContextOwner NetworkContext::MakeURLRequestContext(
       *base::CommandLine::ForCurrentProcess(), is_quic_force_disabled,
       &session_params, quic_context->params());
 
+#if BUILDFLAG(IS_ANDROIDTV)
+  session_params.use_quic_for_unknown_origins = true;
+#endif
+
   session_params.disable_idle_sockets_close_on_memory_pressure =
       params_->disable_idle_sockets_close_on_memory_pressure;