Add a new prefer_aes finch options for QUIC.

chrome/browser/io_thread.h

 // 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.
 
 #ifndef CHROME_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 171 matching lines @@
     Optional<bool> enable_quic;
     Optional<bool> disable_insecure_quic;
     Optional<bool> enable_quic_for_proxies;
     Optional<bool> enable_quic_port_selection;
     Optional<bool> quic_always_require_handshake_confirmation;
     Optional<bool> quic_disable_connection_pooling;
     Optional<float> quic_load_server_info_timeout_srtt_multiplier;
     Optional<bool> quic_enable_connection_racing;
     Optional<bool> quic_enable_non_blocking_io;
     Optional<bool> quic_disable_disk_cache;
+    Optional<bool> quic_prefer_aes;
     Optional<int> quic_max_number_of_lossy_connections;
     Optional<float> quic_packet_loss_threshold;
     Optional<int> quic_socket_receive_buffer_size;
     Optional<size_t> quic_max_packet_length;
     net::QuicTagVector quic_connection_options;
     Optional<std::string> quic_user_agent_id;
     Optional<net::QuicVersionVector> quic_supported_versions;
     Optional<net::HostPortPair> origin_to_force_quic_on;
     bool enable_user_alternate_protocol_ports;
     // NetErrorTabHelper uses |dns_probe_service| to send DNS probes when a
@@ skipping 166 matching lines @@
 
   // Returns true if QUIC's should use non-blocking IO.
   static bool ShouldQuicEnableNonBlockingIO(
       const VariationParameters& quic_trial_params);
 
   // Returns true if QUIC shouldn't load QUIC server information from the disk
   // cache.
   static bool ShouldQuicDisableDiskCache(
       const VariationParameters& quic_trial_params);
 
+  // Returns true if QUIC should prefer AES-GCN even without hardware support.
+  static bool ShouldQuicPreferAes(const VariationParameters& quic_trial_params);
+
   // Returns the maximum number of QUIC connections with high packet loss in a
   // row after which QUIC should be disabled.  Returns 0 if the default value
   // should be used.
   static int GetQuicMaxNumberOfLossyConnections(
       const VariationParameters& quic_trial_params);
 
   // Returns the packet loss rate in fraction after which a QUIC connection is
   // closed and is considered as a lossy connection. Returns 0 if the default
   // value should be used.
   static float GetQuicPacketLossThreshold(
@@ skipping 91 matching lines @@
   bool is_quic_allowed_by_policy_;
 
   const base::TimeTicks creation_time_;
 
   base::WeakPtrFactory<IOThread> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_