Remove support for Alt-Svc/Alternate Protocol Probability

ios/chrome/browser/ios_chrome_io_thread.mm

Index: ios/chrome/browser/ios_chrome_io_thread.mm
diff --git a/ios/chrome/browser/ios_chrome_io_thread.mm b/ios/chrome/browser/ios_chrome_io_thread.mm
index ef492dc3b698b1c7b95aeead7c512743dbbc3229..0fbdab0fa961ddc23a3b212e3ad89d8594aa111a 100644
--- a/ios/chrome/browser/ios_chrome_io_thread.mm
+++ b/ios/chrome/browser/ios_chrome_io_thread.mm
@@ -634,8 +634,6 @@ void IOSChromeIOThread::InitializeNetworkSessionParamsFromGlobals(
       &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);
 
@@ -806,14 +804,6 @@ void IOSChromeIOThread::ConfigureQuicGlobals(
     supported_versions.push_back(version);
     globals->quic_supported_versions.set(supported_versions);
   }
-
-  double threshold =
-      GetAlternativeProtocolProbabilityThreshold(quic_trial_params);
-  if (threshold >= 0 && threshold <= 1) {
-    globals->alternative_service_probability_threshold.set(threshold);
-    globals->http_server_properties->SetAlternativeServiceProbabilityThreshold(
-        threshold);
-  }
 }
 
 bool IOSChromeIOThread::ShouldEnableQuic(base::StringPiece quic_trial_group) {
@@ -842,26 +832,6 @@ net::QuicTagVector IOSChromeIOThread::GetQuicConnectionOptions(
   return net::QuicUtils::ParseQuicConnectionOptions(it->second);
 }
 
-double IOSChromeIOThread::GetAlternativeProtocolProbabilityThreshold(
-    const VariationParameters& quic_trial_params) {
-  double value;
-  // 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 IOSChromeIOThread::ShouldQuicAlwaysRequireHandshakeConfirmation(
     const VariationParameters& quic_trial_params) {
   return base::LowerCaseEqualsASCII(