relnote: Protect against a QUIC crash bug but logging a DFATAL and

net/quic/quic_packet_creator.cc

Index: net/quic/quic_packet_creator.cc
diff --git a/net/quic/quic_packet_creator.cc b/net/quic/quic_packet_creator.cc
index a8afaa7c4a31c0a89e941f95bdd7e3dd0deef7f5..7474b0b17b75bd1f3ebc8cea4b7f683583989e93 100644
--- a/net/quic/quic_packet_creator.cc
+++ b/net/quic/quic_packet_creator.cc
@@ -463,8 +463,11 @@ SerializedPacket QuicPacketCreator::SerializePacket(
     packet.reset(framer_->BuildDataPacket(header, queued_frames_,
                                           large_buffer.get(), packet_size_));
   }
-  LOG_IF(DFATAL, packet == nullptr) << "Failed to serialize "
-                                    << queued_frames_.size() << " frames.";
+  if (packet == nullptr) {
+    LOG(DFATAL) << "Failed to serialize " << queued_frames_.size()
+                << " frames.";
+    return NoPacket();
+  }
 
   OnBuiltFecProtectedPayload(header, packet->FecProtectedData());