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

chrome/browser/io_thread.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 "chrome/browser/io_thread.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 1084 matching lines @@
       &params->enable_tcp_fast_open_for_ssl);
 
   globals.spdy_default_protocol.CopyToIfSet(
       &params->spdy_default_protocol);
   globals.enable_spdy31.CopyToIfSet(&params->enable_spdy31);
   globals.enable_http2.CopyToIfSet(&params->enable_http2);
   globals.parse_alternative_services.CopyToIfSet(
       &params->parse_alternative_services);
   globals.enable_alternative_service_with_different_host.CopyToIfSet(
       &params->enable_alternative_service_with_different_host);
+  globals.alternative_service_probability_threshold.CopyToIfSet(
+      &params->alternative_service_probability_threshold);
 
   globals.enable_npn.CopyToIfSet(&params->enable_npn);
 
   globals.enable_brotli.CopyToIfSet(&params->enable_brotli);
 
   globals.enable_quic.CopyToIfSet(&params->enable_quic);
   globals.disable_quic_on_timeout_with_open_streams.CopyToIfSet(
     &params->disable_quic_on_timeout_with_open_streams);
   globals.enable_quic_for_proxies.CopyToIfSet(&params->enable_quic_for_proxies);
   globals.quic_always_require_handshake_confirmation.CopyToIfSet(
@@ skipping 206 matching lines @@
   quic_user_agent_id.append(content::BuildOSCpuInfo());
   globals->quic_user_agent_id.set(quic_user_agent_id);
 
   net::QuicVersion version = GetQuicVersion(command_line, quic_trial_params);
   if (version != net::QUIC_VERSION_UNSUPPORTED) {
     net::QuicVersionVector supported_versions;
     supported_versions.push_back(version);
     globals->quic_supported_versions.set(supported_versions);
   }
 
+  double threshold = GetAlternativeProtocolProbabilityThreshold(
+      command_line, quic_trial_params);
+  if (threshold >=0 && threshold <= 1) {
+    globals->alternative_service_probability_threshold.set(threshold);
+    globals->http_server_properties->SetAlternativeServiceProbabilityThreshold(
+        threshold);
+  }
+
   if (command_line.HasSwitch(switches::kOriginToForceQuicOn)) {
     net::HostPortPair quic_origin =
         net::HostPortPair::FromString(
             command_line.GetSwitchValueASCII(switches::kOriginToForceQuicOn));
     if (!quic_origin.IsEmpty()) {
       globals->origin_to_force_quic_on.set(quic_origin);
     }
   }
 }
 
@@ skipping 57 matching lines @@
 
   VariationParameters::const_iterator it =
       quic_trial_params.find("connection_options");
   if (it == quic_trial_params.end()) {
     return net::QuicTagVector();
   }
 
   return net::QuicUtils::ParseQuicConnectionOptions(it->second);
 }
 
+double IOThread::GetAlternativeProtocolProbabilityThreshold(
+    const base::CommandLine& command_line,
+    const VariationParameters& quic_trial_params) {
+  double value;
+  if (command_line.HasSwitch(
+          switches::kAlternativeServiceProbabilityThreshold)) {
+    if (base::StringToDouble(
+            command_line.GetSwitchValueASCII(
+                switches::kAlternativeServiceProbabilityThreshold),
+            &value)) {
+      return value;
+    }
+  }
+  if (command_line.HasSwitch(switches::kEnableQuic)) {
+    return 0;
+  }
+  // TODO(bnc): Remove when new parameter name rolls out and server
+  // configuration is changed.
+  if (base::StringToDouble(
+          GetVariationParam(quic_trial_params,
+                            "alternate_protocol_probability_threshold"),
+          &value)) {
+    return value;
+  }
+  if (base::StringToDouble(
+          GetVariationParam(quic_trial_params,
+                            "alternative_service_probability_threshold"),
+          &value)) {
+    return value;
+  }
+  return -1;
+}
+
 bool IOThread::ShouldQuicAlwaysRequireHandshakeConfirmation(
     const VariationParameters& quic_trial_params) {
   return base::LowerCaseEqualsASCII(
       GetVariationParam(quic_trial_params,
                         "always_require_handshake_confirmation"),
       "true");
 }
 
 bool IOThread::ShouldQuicDisableConnectionPooling(
     const VariationParameters& quic_trial_params) {
@@ skipping 322 matching lines @@
       std::move(job_factory);
 
   context->set_job_factory(
       globals->proxy_script_fetcher_url_request_job_factory.get());
 
   // TODO(rtenneti): We should probably use HttpServerPropertiesManager for the
   // system URLRequestContext too. There's no reason this should be tied to a
   // profile.
   return context;
 }