Add extra QUIC_BUG logging in QuicPacketCreator. No functional change. Not flag protected.

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 e60e2c80a9a15757eeac5b116da8a29624f8665c..efaf1136b216def9ec307c27c8cced55c339841a 100644
--- a/net/quic/quic_packet_creator.cc
+++ b/net/quic/quic_packet_creator.cc
@@ -118,7 +118,9 @@ void QuicPacketCreator::UpdatePacketNumberLength(
   if (FLAGS_quic_simple_packet_number_length && !queued_frames_.empty()) {
     // Don't change creator state if there are frames queued.
     QUIC_BUG << "Called UpdatePacketNumberLength with " << queued_frames_.size()
-             << " queued_frames.";
+             << " queued_frames.  First frame type:"
+             << queued_frames_.front().type
+             << " last frame type:" << queued_frames_.back().type;
     return;
   }