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

components/cronet/android/cronet_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/cronet_url_request_context_adapter.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <map>
 #include <utility>
@@ skipping 466 matching lines @@
   if (config->enable_sdch) {
     DCHECK(context_->sdch_manager());
     sdch_owner_.reset(
         new net::SdchOwner(context_->sdch_manager(), context_.get()));
     if (json_pref_store_) {
       sdch_owner_->EnablePersistentStorage(
           make_scoped_ptr(new SdchOwnerPrefStorage(json_pref_store_.get())));
     }
   }
 
+  // Currently (circa M39) enabling QUIC requires setting probability threshold.
   if (config->enable_quic) {
+    context_->http_server_properties()
+        ->SetAlternativeServiceProbabilityThreshold(0.0f);
     for (auto hint = config->quic_hints.begin();
          hint != config->quic_hints.end(); ++hint) {
       const URLRequestContextConfig::QuicHint& quic_hint = **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());
     }
   }
 
   // Iterate through PKP configuration for every host.
   for (const auto& pkp : config->pkp_list) {
     // Add the host pinning.
     context_->transport_security_state()->AddHPKP(
         pkp->host, pkp->expiration_date, pkp->include_subdomains,
         pkp->pin_hashes, GURL::EmptyGURL());
   }
@@ skipping 264 matching lines @@
     JNIEnv* env,
     const JavaParamRef<jclass>& jcaller) {
   base::StatisticsRecorder::Initialize();
   std::vector<uint8_t> data;
   if (!HistogramManager::GetInstance()->GetDeltas(&data))
     return ScopedJavaLocalRef<jbyteArray>();
   return base::android::ToJavaByteArray(env, &data[0], data.size());
 }
 
 }  // namespace cronet