Internal QUICHE change

PiperOrigin-RevId: 332070542
Change-Id: Ifc8b12a9f7f04611d2b9ff25b48e46848827aef3

quic/core/http/end_to_end_test.cc

diff --git a/quic/core/http/end_to_end_test.cc b/quic/core/http/end_to_end_test.cc
index a36017c..d5bfc79 100644
--- a/quic/core/http/end_to_end_test.cc
+++ b/quic/core/http/end_to_end_test.cc
@@ -201,6 +201,7 @@
     // Enable fixes for bugs found in tests and prod.
     SetQuicRestartFlag(quic_enable_tls_resumption_v4, true);
     SetQuicRestartFlag(quic_enable_zero_rtt_for_tls_v2, true);
+    SetQuicReloadableFlag(quic_fix_out_of_order_sending, true);
   }
 
   ~EndToEndTest() override { QuicRecyclePort(server_address_.port()); }
@@ -530,8 +531,7 @@
       if (server_connection != nullptr) {
         QuicConnectionStats server_stats = server_connection->GetStats();
         if (!had_packet_loss) {
-          EXPECT_EQ(0u, server_stats.packets_lost -
-                            server_stats.packet_spuriously_detected_lost);
+          EXPECT_EQ(0u, server_stats.packets_lost);
         }
         EXPECT_EQ(0u, server_stats.packets_discarded);
         EXPECT_EQ(server_session->user_agent_id().value_or("MissingUserAgent"),
@@ -1496,11 +1496,6 @@
   EXPECT_FALSE(client_session->ReceivedInchoateReject());
   EXPECT_FALSE(client_->client()->EarlyDataAccepted());
   EXPECT_FALSE(client_->client()->ReceivedInchoateReject());
-  while (client_->client()->connected() &&
-         client_session->connection()->HasPendingAcks()) {
-    // Flush all pending acks.
-    client_->client()->WaitForEvents();
-  }
   VerifyCleanConnection(false);
 }
 

quic/core/quic_connection.cc

diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index bae994f..83f7fd7 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -4781,11 +4781,20 @@
     DCHECK(!is_mtu_discovery);
     return LEGACY_VERSION_ENCAPSULATE;
   }
-  if (version().CanSendCoalescedPackets() && !IsHandshakeConfirmed() &&
-      !is_mtu_discovery) {
-    // Before receiving ACK for any 1-RTT packets, always try to coalesce
-    // packet (except MTU discovery packet).
-    return COALESCE;
+  if (version().CanSendCoalescedPackets() && !is_mtu_discovery) {
+    if (!IsHandshakeConfirmed()) {
+      // Before receiving ACK for any 1-RTT packets, always try to coalesce
+      // packet (except MTU discovery packet).
+      return COALESCE;
+    }
+    if (GetQuicReloadableFlag(quic_fix_out_of_order_sending)) {
+      QUIC_RELOADABLE_FLAG_COUNT(quic_fix_out_of_order_sending);
+      if (coalesced_packet_.length() > 0) {
+        // If the coalescer is not empty, let this packet go through coalescer
+        // to avoid potential out of order sending.
+        return COALESCE;
+      }
+    }
   }
   if (!buffered_packets_.empty() || HandleWriteBlocked()) {
     return BUFFER;