Fix a QUIC DCHECK flakiness caused by not checking if a packet is

net/quic/quic_sent_packet_manager_test.cc

Index: net/quic/quic_sent_packet_manager_test.cc
diff --git a/net/quic/quic_sent_packet_manager_test.cc b/net/quic/quic_sent_packet_manager_test.cc
index 175a80de2e21b9d96eb7d6c3dccec7d86f588ac7..77875d7c2de03a839e79b40ca06d2c4e0f249920 100644
--- a/net/quic/quic_sent_packet_manager_test.cc
+++ b/net/quic/quic_sent_packet_manager_test.cc
@@ -1019,6 +1019,25 @@ TEST_F(QuicSentPacketManagerTest, CryptoHandshakeTimeout) {
   EXPECT_FALSE(QuicSentPacketManagerPeer::HasUnackedCryptoPackets(&manager_));
 }
 
+TEST_F(QuicSentPacketManagerTest, CryptoHandshakeTimeoutUnsentDataPacket) {
+  // Send 2 crypto packets and serialize 1 data packet.
+  const size_t kNumSentCryptoPackets = 2;
+  for (size_t i = 1; i <= kNumSentCryptoPackets; ++i) {
+    SendCryptoPacket(i);
+  }
+  SerializedPacket packet(CreateDataPacket(3));
+  manager_.OnSerializedPacket(packet);
+  EXPECT_TRUE(QuicSentPacketManagerPeer::HasUnackedCryptoPackets(&manager_));
+
+  // Retransmit 2 crypto packets, but not the serialized packet.
+  EXPECT_CALL(*send_algorithm_, OnPacketAbandoned(_, _)).Times(2);
+  manager_.OnRetransmissionTimeout();
+  RetransmitNextPacket(6);
+  RetransmitNextPacket(7);
+  EXPECT_FALSE(manager_.HasPendingRetransmissions());
+  EXPECT_TRUE(QuicSentPacketManagerPeer::HasUnackedCryptoPackets(&manager_));
+}
+
 TEST_F(QuicSentPacketManagerTest, RetransmissionTimeout) {
   // Send 100 packets and then ensure all are abandoned when the RTO fires.
   const size_t kNumSentPackets = 100;