Server push cancellation: add a finch trial parameter

components/network_session_configurator/network_session_configurator.cc

 // Copyright 2016 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/network_session_configurator/network_session_configurator.h"
 
 #include <map>
 #include <unordered_set>
 
 #include "base/metrics/field_trial.h"
@@ skipping 314 matching lines @@
     return value;
   }
   return 0;
 }
 
 net::QuicVersion GetQuicVersion(const VariationParameters& quic_trial_params) {
   return network_session_configurator::ParseQuicVersion(
       GetVariationParam(quic_trial_params, "quic_version"));
 }
 
+bool ShouldEnableServerPushCancelation(
+    const VariationParameters& quic_trial_params) {
+  return base::LowerCaseEqualsASCII(
+      GetVariationParam(quic_trial_params, "enable_server_push_cancellation"),
+      "true");
+}
+
 void ConfigureQuicParams(base::StringPiece quic_trial_group,
                          const VariationParameters& quic_trial_params,
                          bool is_quic_force_disabled,
                          bool is_quic_force_enabled,
                          const std::string& quic_user_agent_id,
                          net::HttpNetworkSession::Params* params) {
   params->enable_quic = ShouldEnableQuic(
       quic_trial_group, quic_trial_params, is_quic_force_disabled,
       is_quic_force_enabled);
   params->mark_quic_broken_when_network_blackholes =
       ShouldMarkQuicBrokenWhenNetworkBlackholes(quic_trial_params);
+
+  params->enable_server_push_cancellation =
+      ShouldEnableServerPushCancelation(quic_trial_params);
+
   params->retry_without_alt_svc_on_quic_errors =
       ShouldRetryWithoutAltSvcOnQuicErrors(quic_trial_params);
   params->enable_quic_alternative_service_with_different_host =
       ShouldQuicEnableAlternativeServicesForDifferentHost(quic_trial_params);
 
   if (params->enable_quic) {
     params->quic_always_require_handshake_confirmation =
         ShouldQuicAlwaysRequireHandshakeConfirmation(quic_trial_params);
     params->quic_disable_connection_pooling =
         ShouldQuicDisableConnectionPooling(quic_trial_params);
@@ skipping 122 matching lines @@
   ConfigureTCPFastOpenParams(tfo_trial_group, params);
 
   std::map<std::string, std::string> proxy_preconnects_trial_params;
   variations::GetVariationParams("NetProxyPreconnects",
                                  &proxy_preconnects_trial_params);
   ConfigureOptimizePreconnectsToProxiesParams(proxy_preconnects_trial_params,
                                               params);
 }
 
 }  // namespace network_session_configurator