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

components/cronet/android/url_request_context_adapter.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 "components/cronet/android/url_request_context_adapter.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <limits>
 #include <utility>
@@ skipping 146 matching lines @@
   config_->ConfigureURLRequestContextBuilder(&context_builder, nullptr);
 
   context_ = context_builder.Build();
 
   if (config_->enable_sdch) {
     DCHECK(context_->sdch_manager());
     sdch_owner_.reset(
         new net::SdchOwner(context_->sdch_manager(), context_.get()));
   }
 
+  // Currently (circa M39) enabling QUIC requires setting probability threshold.
   if (config_->enable_quic) {
+    context_->http_server_properties()
+        ->SetAlternativeServiceProbabilityThreshold(0.0f);
     for (size_t hint = 0; hint < config_->quic_hints.size(); ++hint) {
       const URLRequestContextConfig::QuicHint& quic_hint =
           *config_->quic_hints[hint];
       if (quic_hint.host.empty()) {
         LOG(ERROR) << "Empty QUIC hint host: " << quic_hint.host;
         continue;
       }
 
       url::CanonHostInfo host_info;
       std::string canon_host(net::CanonicalizeHost(quic_hint.host, &host_info));
@@ skipping 16 matching lines @@
                    << quic_hint.alternate_port;
         continue;
       }
 
       net::HostPortPair quic_hint_host_port_pair(canon_host,
                                                  quic_hint.port);
       net::AlternativeService alternative_service(
           net::AlternateProtocol::QUIC, "",
           static_cast<uint16_t>(quic_hint.alternate_port));
       context_->http_server_properties()->SetAlternativeService(
-          quic_hint_host_port_pair, alternative_service, base::Time::Max());
+          quic_hint_host_port_pair, alternative_service, 1.0f,
+          base::Time::Max());
     }
   }
   load_disable_cache_ = config_->load_disable_cache;
   config_.reset(NULL);
 
   if (VLOG_IS_ON(2)) {
     net_log_observer_.reset(new NetLogObserver());
     context_->net_log()->DeprecatedAddObserver(
         net_log_observer_.get(),
         net::NetLogCaptureMode::IncludeCookiesAndCredentials());
@@ skipping 98 matching lines @@
     write_to_file_observer_.reset();
   }
 }
 
 void NetLogObserver::OnAddEntry(const net::NetLog::Entry& entry) {
   VLOG(2) << "Net log entry: type=" << entry.type()
           << ", source=" << entry.source().type << ", phase=" << entry.phase();
 }
 
 }  // namespace cronet