Make QUIC's SerializedPacket contain QuicFrames, rather than a pointer

net/quic/quic_sent_packet_manager.cc

Index: net/quic/quic_sent_packet_manager.cc
diff --git a/net/quic/quic_sent_packet_manager.cc b/net/quic/quic_sent_packet_manager.cc
index 8b7623dc1a8f168d4c88fe43640171987465e4a9..5f0474cea8a3e7735c73f52da45009f84f243dd4 100644
--- a/net/quic/quic_sent_packet_manager.cc
+++ b/net/quic/quic_sent_packet_manager.cc
@@ -583,9 +583,6 @@ bool QuicSentPacketManager::OnPacketSent(
   unacked_packets_.AddSentPacket(serialized_packet, original_packet_number,
                                  transmission_type, sent_time, bytes,
                                  in_flight);
-
-  // Take ownership of the retransmittable frames before exiting.
-  serialized_packet->retransmittable_frames = nullptr;
   // Reset the retransmission timer anytime a pending packet is sent.
   return in_flight;
 }