Update from https://crrev.com/307330

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index c33aec55e26698650b0069184588f3446a9f8ac3..74d175802e2bce2291396518d1ae5ba7ec02fb0e 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -192,7 +192,8 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
                                bool is_server,
                                bool is_secure,
                                const QuicVersionVector& supported_versions)
-    : framer_(supported_versions, helper->GetClock()->ApproximateNow(),
+    : framer_(supported_versions,
+              helper->GetClock()->ApproximateNow(),
               is_server),
       helper_(helper),
       writer_(writer_factory.Create(this)),
@@ -213,6 +214,7 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
       largest_seen_packet_with_stop_waiting_(0),
       max_undecryptable_packets_(0),
       pending_version_negotiation_packet_(false),
+      silent_close_enabled_(false),
       received_packet_manager_(&stats_),
       ack_queued_(false),
       num_packets_received_since_last_ack_sent_(0),
@@ -230,7 +232,9 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
       time_of_last_sent_new_packet_(clock_->ApproximateNow()),
       sequence_number_of_last_sent_packet_(0),
       sent_packet_manager_(
-          is_server, clock_, &stats_,
+          is_server,
+          clock_,
+          &stats_,
           FLAGS_quic_use_bbr_congestion_control ? kBBR : kCubic,
           FLAGS_quic_use_time_loss_detection ? kTime : kNack,
           is_secure),
@@ -268,6 +272,9 @@ void QuicConnection::SetFromConfig(const QuicConfig& config) {
   if (config.negotiated()) {
     SetNetworkTimeouts(QuicTime::Delta::Infinite(),
                        config.IdleConnectionStateLifetime());
+    if (FLAGS_quic_allow_silent_close && config.SilentClose()) {
+      silent_close_enabled_ = true;
+    }
   } else {
     SetNetworkTimeouts(config.max_time_before_crypto_handshake(),
                        config.max_idle_time_before_crypto_handshake());
@@ -313,14 +320,8 @@ bool QuicConnection::SelectMutualVersion(
 void QuicConnection::OnError(QuicFramer* framer) {
   // Packets that we can not or have not decrypted are dropped.
   // TODO(rch): add stats to measure this.
-  if (FLAGS_quic_drop_junk_packets) {
-    if (!connected_ || last_packet_decrypted_ == false) {
-      return;
-    }
-  } else {
-    if (!connected_ || framer->error() == QUIC_DECRYPTION_FAILURE) {
-      return;
-    }
+  if (!connected_ || last_packet_decrypted_ == false) {
+    return;
   }
   SendConnectionCloseWithDetails(framer->error(), framer->detailed_error());
 }
@@ -1854,6 +1855,12 @@ void QuicConnection::SendConnectionClosePacket(QuicErrorCode error,
   DVLOG(1) << ENDPOINT << "Force closing " << connection_id()
            << " with error " << QuicUtils::ErrorToString(error)
            << " (" << error << ") " << details;
+  // Don't send explicit connection close packets for timeouts.
+  // This is particularly important on mobile, where connections are short.
+  if (silent_close_enabled_ &&
+      error == QuicErrorCode::QUIC_CONNECTION_TIMED_OUT) {
+    return;
+  }
   ScopedPacketBundler ack_bundler(this, SEND_ACK);
   QuicConnectionCloseFrame* frame = new QuicConnectionCloseFrame();
   frame->error_code = error;