Add a new prefer_aes finch options for QUIC.

chrome/browser/io_thread_unittest.cc

Index: chrome/browser/io_thread_unittest.cc
diff --git a/chrome/browser/io_thread_unittest.cc b/chrome/browser/io_thread_unittest.cc
index 03e3dc4aea2e0524c99b166a38aa9cce87631663..6f460bd243e84f5b554d0fc0ac63e522b3da80cb 100644
--- a/chrome/browser/io_thread_unittest.cc
+++ b/chrome/browser/io_thread_unittest.cc
@@ -188,6 +188,7 @@ TEST_F(IOThreadTest, EnableQuicFromFieldTrialGroup) {
   EXPECT_FALSE(params.quic_enable_connection_racing);
   EXPECT_FALSE(params.quic_enable_non_blocking_io);
   EXPECT_FALSE(params.quic_disable_disk_cache);
+  EXPECT_FALSE(params.quic_prefer_aes);
   EXPECT_EQ(0, params.quic_max_number_of_lossy_connections);
   EXPECT_EQ(1.0f, params.quic_packet_loss_threshold);
   EXPECT_FALSE(IOThread::ShouldEnableQuicForDataReductionProxy());
@@ -363,6 +364,15 @@ TEST_F(IOThreadTest, QuicDisableDiskCache) {
   EXPECT_TRUE(params.quic_disable_disk_cache);
 }
 
+TEST_F(IOThreadTest, QuicPreferAes) {
+  field_trial_group_ = "Enabled";
+  field_trial_params_["prefer_aes"] = "true";
+  ConfigureQuicGlobals();
+  net::HttpNetworkSession::Params params;
+  InitializeNetworkSessionParams(&params);
+  EXPECT_TRUE(params.quic_prefer_aes);
+}
+
 TEST_F(IOThreadTest, QuicMaxNumberOfLossyConnectionsFieldTrialParams) {
   field_trial_group_ = "Enabled";
   field_trial_params_["max_number_of_lossy_connections"] = "5";